DE1603786A1 - Pneumatic driving device for nails, staples or the like. - Google Patents

Description

fastener Corporation,! Franklin Park, Illinois., TT.St.A.

Pneumatic drive-in device for hail, clamps ocLdgl <

The invention relates to a pneumatic driving device (Nailing machine) for hail, staples or the like «with a housing, a cylinder arranged in it, a working piston displaceable in this, a main valve, which the upper end of the cylinder optionally with a in the housing arranged air chamber and the outside air connects, and a return chamber, which connects to the lower End of the cylinder is connected.

Such driving devices are known. When a release lever is pressed, a release valve is actuated, which opens the main valve and pressurized air into the upper one Rope dee cylinder flows in. This compressed air drives

109812/0285

the working piston downwards in one working stroke, with a nail or the like being hammered into the workpiece «The The working piston normally remains in the lowest position at the end of the working stroke until the release lever released and the space above the piston is connected to the outside air. However, there are also input devices known with automatic return of the working piston, in which the piston is returned to its starting position without releasing the release lever o In both cases, the piston is returned through the space Compressed air below the piston when the space above the piston is connected to the outside air »After the Return, the piston must remain in its rest position until the next working stroke takes place »

The known pneumatic return devices generally have the disadvantage that before the full completion of the working stroke compressed air flows into the return chamber and the space under the piston, what a Reduction of the impact force in the decisive final phase of the working stroke. In addition, surrender This causes difficulties in driving devices with automatic piston return, in which the Druokanatieg A compressed air signal is sent in the return chamber for reversing the working pressure «

SAD ORfQINAL 109812/0285

The invention is based on the object of "avoiding these difficulties" and an improved pneumatic To create driving device in which the return chamber only after full completion of the working stroke Compressed air is supplied, s, o that no weakening of the driving force occurs at the end of the stroke and with devices with automatic piston return no premature change control can take place.

The essence of the invention is that the working piston contains two spaced apart hats on its circumferential surface, the first of which contains a sealing ring for sealing against the cylinder wall, while the second is in communication with the space above the working piston through bores and one includes resilient ring lies down with such a force against the bottom of the groove that it is only at the contact ä up a predetermined pressure difference from the base of the groove takes off and leaves the air in the space under the piston occur.

The pneumatic driving device according to the invention has a housing with a handle part, the cavity of which is a Forms air chamber, and a head part that contains a working cylinder. The working piston is in the cylinder arranged »A main valve controls the connection of the

109812/02 85

upper cylinder parts with the air chamber or the outside air o The main valve is controlled by a release valve, which is actuated by a release lever »The driving device can also have an automatic piston return to have. (Further details can be found in the Obergfell Oase applications submitted at the same time and 76 of the applicant.) The head part of the housing contains a return chamber which is connected to the cylinder through openings arranged on the lower part of the cylinder. The piston contains two circumferential grooves arranged at a distance from one another on its circumference. The first groove bears a sealing ring that seals the piston against the inside of the cylinder »the second groove contains.eine elastic hanging, preferably of circular cross-section. The working piston contains bores that form the bottom of the Connect the second groove to the tree above the piston. The elastic ring opposes with such a force the reason for the groove that it only occurs when a predetermined pressure difference occurs between the space above and the space below the piston is lifted from the bottom of the groove, so that compressed air from the space above the piston into the space can flow under the piston and into the return chamber.

The pressure rises during the working stroke of the piston in the space above the piston initially does not indicate that the

109812/0 285

elastic input is lifted from the bottom of his hat. As soon however, the working cage has reached the end of its stroke, the pressure in the tree above the piston rises until it settles approaches the pressure of the air chamber. The reason for this is that the check valve opens, so that compressed air flows into the space under the piston and the return chamber. The elastic one The ring then rests against the bottom of the groove again, so that the non-return valve closes and the piston closes Connection of the upper part of the cylinder with the outside air in the initial position is returned «The upper end of the cylinder has an enlarged diameter, creating a Paragraph arises against which the sealing ring of the first groove lies when the piston is in its uppermost position located in order to prevent undesired lowering of the piston «,

Further details of the pneumatic Eintreibvorrioh- ( tüng according to the invention emerge from the following description of an embodiment with reference to the drawing.

Pig. 1 is a partial section through a pneumatic Driving device according to the inventionf the parts are in their rest position shown »

Pig. 2 is a cut like Pig »1, showing the position of the Showed ropes at the end of the working hood

Figo 3 is a partial section along 3-3 of the Pig. To

Pig * 4 is an enlarged partial section according to 4-4 of FIG. 3o

The pneumatic lathering device is denoted by the general reference number 10. It contains a housing 12 with an essentially vertically arranged front head part 12a and a rear handle part 12b _# the cavity of which forms an air chamber 16. A pressure medium, preferably compressed air, is fed to the air chamber through a flexible line (not shown in the drawing) ο The drive device for the driving device 10 contains a working cylinder 18 which is arranged in a cavity 12c of the head part 12a, and whose upper end 18a can be optionally connected to the air chamber and the outside air through a main valve 20 »The upper, open end of the cylinder 18 normally engages a diaphragm 40 of main valve 20. The main valve is controlled by a release valve 24. A working piston 26, which is connected to a plunger 28, is slidably arranged in the cylinder 18. An outlet valve designated by the general reference number 32 controls the connection of the upper end of the cylinder 18 with the outside air.

If an Artest * ir ^ r ^^ iget, that will be Release valve 24 actuated, e & that compressed air from the wind

109812/0285

- 7 -

Kessel 16 enters the upper end of the cylinder 18 and drives the working piston 26 downwards, the plunger gripping a hail or glove pushed into the mouthpiece 36 in order to knock it into the workpiece The upper end of the cylinder 18 is controlled by the main valve 20 which contains the diaphragm 40. The outer band of the membrane is clamped between a cover 4-2 and the head part 12a of the housing 12. The membrane normally rests against the end face of the upper end 18a of the cylinder 18. The diaphragm 40 is urged by a spring 44 between the cover 42 and the diaphragm 40 is disposed against the upper end of the cylinder 18th The underside of the membrane is constantly in engagement with the compressed air via a wide channel 46 and an inlet space 47, so that this acts on the underside of the membrane and tries to lift the latter from the end face of the cylinder 18. However, compressed air also reaches the space above the membrane via a channel 48 when the driving device is in the rest position. Since the force exerted on the top of the diaphragm 40 is greater than the force exerted on its underside, the diaphragm 40 will normally be in the pig position. held. If, however, the space above the membrane is vented, the one entering through the wide channel 46 lifts

109812/028

Compressed air down the membrane 40 from the upper edge of the cylinder, so that compressed air over a wide cross-section into the enters the upper end of the cylinder 18 and drives the working piston 26 downward in one working stroke.

Because the driving device 10 is in the rest position and while the working piston is being returned to its starting position, the upper end of the cylinder 18 is connected to the outside air via the outlet valve 32. In the illustrated embodiment, the outlet valve 32 contains a hollow valve stem 50 which is connected to the diaphragm and which connects the upper end of the cylinder 18 to the outside air via a suitable outlet duct 52. However, if a working stroke is to be triggered, it is necessary to close the upper end of the cylinder 18 from the outside air. For this purpose, an elastic valve seat 54 is arranged on the cover 42 opposite the upper end of the valve stem 50, which comes into engagement with the valve stem when the diaphragm is raised at the beginning of a working stroke, whereby the connection of the upper end of the cylinder 18 with the outside air is interrupted (position of Fig »2). Since the valve seat 54 experiences a strong impact, the cover is preferably made of hardened steel. This also prevents damage to the cover 42 if it is accidentally

109812/0285 BADOR ₁ G ₁ NA ₁ .

with a tough one. Surface comes into engagement "

The release valve 24, through which the working stroke is initiated, can be designed in a manner known per se. In the illustrated embodiment, it includes a Tentilkammer 58 with two oppositely arranged openings 60 and 62 which constitute valve seats, which are alternately connected to a valve member 63 in engagement ₀

qli'e-d.

The valve 63 can, for example, be designed as a Y-valve ball 64 with a downwardly directed pin 66. The opening 60 is normally in communication with the air chamber 16, while the opening 62 represents an outlet opening through which the valve chamber 58 is vented when the valve ball 64 is lifted therefrom (position of FIG. 2). The pin 66 is actuated by a release lever 68. "At home, the driving device is in the rest position, the valve ball 64 rests against the opening 62. If the release lever is pressed, the opening 62 is released, the valve ball 64 simultaneously closing the opening 60 Opening 70, which is connected to the space above membrane 40 via a channel 48. If the release lever 68 is released, the opening 70 is connected to the air chamber 16 via the opening 60. If the release lever 68 is pressed and the valve ball 64 is lifted so that B.

109812/0285

- ίο -

the opening 60 is closed, the opening 70 is in connection with the outside air.

For the purpose of returning the working piston 26 to the rest position, a return chamber 76 is provided, which with the lower end of the cylinder 18 over a multi

P number of openings 78 is in communication »The working piston 26 is bell-shaped and has a central cavity 26a which is open at the top. The circumferential surface of the working piston 26 has two circumferential grooves 82 and 84 arranged at a distance from one another.The upper groove 82 serves to seal against the cylinder, while the lower groove 84 forms a cable of a check valve which supplies the return chamber 76 with compressed air. A sealing ring 86 is arranged in the upper cap 82, which seals the piston against the inner wall of the cylinder 18. To circumvent this seal, a plurality of bores 90 are provided in the piston, which connect the lower groove 84 with the cavity 26a of the piston (see FIG. 4). An elastic ring 92, which forms the movable valve member, is arranged in the groove 84. The elastic ring 82 normally lies against the openings of the bores 90 «The inner diameter" d "(Fig. 3) of the elastic ring is smaller in the relaxed state than the inner diameter" D ^{H of} the groove 84. The elastic ring 92 has a cross section

1098 12/0285

a diameter or a width "t" (Mg. 4) ι the smaller is the hat 84 as the width "T". Upon occurrence of a predetermined pressure differential between the space above and the space under the working piston 26, the elastic ring 92 is lifted from the openings of the bores 90, see above that compressed air from the space above the working piston flows past the elastic ring 92 and into the return chamber 76 can occur.

It is of course required that the plunger 28 be sufficient to be sealed in order to prevent premature escape of the air required for the piston return »Zu For this purpose, a sealing washer 77 is provided at the lower end of the head part 12a, the opening 77a of which the plunger 28 surrounds. It is necessary to provide enough air for the return of the working piston; the length of the However, return air should not be so large that an excessively large air consumption arises or that after return of the working piston, the pressure in the return chamber is rapidly reduced by the pressure that seeps through at the opening 77a Air is prevented «. It has been found that a ratio of the volume of the return air to the volume of the Piston displacement from 2 to 3 is sufficient.

In order to intercept the working stroke of the piston 26 and to achieve a further seal of the plunger when the working

108812/0285

piston is in its lowest position, an elastic, annular buffer 96 is arranged at the lower end of the cylinder 18, with which the piston, as shown in FIG. 2, comes into engagement in its lowest position _{or the like}

Preferably, the cylinder 18 is only in its position in the cavity 12c by the pressure acting on it held, whereby a quick disassembly for the purpose of repair or replacement is made possible. The cylinder 18 includes an outwardly directed flange 18b which engages an inwardly directed projection 12d of the Cavity 12c is. The seal is made by a sealing ring 98, the space between the inner Wall of the head part 12a and the cylinder 18 in the annular space 47 and the return chamber 76 divided. The lower end of the cylinder 18 has an outwardly directed splash 18c, which engages the inner wall of the cavity 12c to center the lower end of the cylinder 18. The air pressure in the annulus 47 presses on the flange 18b to hold the cylinder 18 in the desired position. Of the The distance of the cylinder 18 from the wall of the head part 12a protects the cylinder 18 against damage from impacts the head part 12a of the driving device.

To the working piston 26 of the driving device between to keep the working strokes in its rest position and a

, ■■: ■ / ■ ■■■: ■. BATH ORIGINAL

109812/078 5

To prevent unintentional lowering of the piston, the upper sealing ring 86 rests against a step or shoulder 18d (FIG. 2) at the lower end of the enlarged cylinder part 18e of the cylinder 18 when the piston is in the rest position best seen in Figo 2 = ' ^:

Although the principle of operation of the pneumatic sintering device is already apparent from the above description, it is intended for the sake of easier understanding once briefly summarized = the working piston 26 with the ram 28 performs a working stroke when the upper end of the cylinder 18 is connected to the air chamber 16. Since the working piston does not initially encounter any significant resistance as it moves downwards, the pressure rises above the working piston only then so far that the elastic ring 92 is lifted from the bottom of the hat 84, |

when the piston 26 as shown in Figo 2, has reached its lowermost position _o In this position, the pressure above the working piston 26, until the pressure of the air chamber 16 approaches increases. The sealing ring 92, which acts as a valve member, is therefore raised from the openings of the bores, so that compressed air flows through the openings 78 of the cylinder into the return chamber 76. During the short period of return of the working piston, there is no significant

BATH ORIGINAL 109812/0285

-H-

Air trapped under piston 26 is lost. To When the release lever 68 is released, the main valve closes the upper end of the cylinder 18 and connects it Via the outlet valve 32 with the outside air «The compressed air contained in the return chamber» 76 flows through the ^ Openings 78 in the space below the working piston and guides it with the plunger into its starting position return. The remaining return air escapes past the ram through the opening 77a, around the driving device to prepare for another work stroke «

It goes without saying that a number of design changes are possible without leaving the scope of the concept of the invention To exceed

109812/0285

Claims (10)

Claims 1. / Pneumatic driving device for hail, staples or the like with a housing, one arranged therein Cylinder, a working piston that can be displaced in this, a main valve, which is the upper end of the cylinder optionally with an air chamber arranged in the housing and the outside air, and a return chamber, which is connected to the lower end of the cylinder by openings, characterized by the combination, that the working piston (26) has two im Includes spaced apart hats (82, 84), of which the first contains a laughing ring (86) for sealing against the cylinder wall, while the second (84) through bores (90) with the seam above the working piston in connection and an elastic Ring (92) contains, which lies against the bottom of the hat (84) with such a force that it is only when BAD OBIGlNAU 109812/0285 Occurrence of a predetermined pressure difference from the bottom of the hat (84) is lifted and the air into the space uiitor of the. . Working piston and into the return chamber can enter. 2ο driving device according to claim 1, characterized in that that the elastic ring (92) has a circular Has cross-section. ο driving device according to claim 2, characterized in that that the inner diameter (d) of the elastic ring (92) in the relaxed state is smaller than that Diameter (D) at the bottom of the hat (84), and that its cross-sectional diameter (t) is smaller than the width (T) the hat (84) ο Driving device according to one of Claims 1 to 3, characterized in that the working piston is bell-shaped is formed and has an upper cavity (26a) through holes (90) with the bottom of the second hat (84) is connected » 5 · driving device according to one of claims 1 to 4, characterized in that at the lower end of the cylinder (18) an elastic, annular buffer (96) is arranged, which in the lower position of the piston (26) with this comes into sealing engagement. 10 9 8 12/0785 6 _β driving device according to one of claims 1 to 5 »characterized in that the upper end (18a) of the cylinder (18) has an enlarged diameter with a shoulder (I8d) against which the first sealing ring (82) rests when the piston (26) is in its uppermost position »- BAD OBtGlNAU 109812/0285 Blank page