Patent Grant
7028877
The invention relates to a combustion-operated working tool, in particular a setting tool for fastening elements, having a housing body, which has a cylindrical recess and a piston chamber communicating therewith for receiving a piston; an impact plate, which is arranged separately spaced opposite to the cylindrical recess facing the housing body and can be moved away from same, and a packing sleeve arranged in the cylindrical recess and projecting therefrom.
DE 199 05 896 A1 discloses a powder-power operated setting tool, which has a first part in the form of a guide cylinder and a second part in the form of an impact plate. Both parts are essentially arranged coaxial to each other and can be displaced parallel to each other in the setting direction. The end zone of the first part facing towards the impact plate has a cartridge bearing, which serves to receive the cartridges. In the setting direction a cartridge chamber communicates with the cartridge bearing and a driver piston is arranged axially displaceable in the chamber. The piston chamber communicates with the cartridge chamber via a connection bore hole.
The impact plate has an axially displaceable mounted bushing on its side facing the guide cylinder. Immediately after firing the cartridge the seal bushing will be urged against the guide cylinder by the accumulating very high pressure if there is a still unused cartridge present in the cartridge bearing and if the impact plate is shifted in towards the guide cylinder, which results in a very reliable sealing of the cartridge bearing in the zone between the guide cylinder and the impact plate.
The packing sleeve is held on the impact plate using an annular discoid elastic membrane. This membrane is fastened securely to the setting side surface of the impact plate. The sealing element has a sealing projection on its setting side surface, which is formed from a peripheral thin-walled projection.
The object of the invention is to provide a further working tool of the aforementioned type. In particular, the impact plate has a very slight weight such that it can be driven quickly using as low a power as possible.
The solution of the problem is solved according to the invention by a combustion-operated working tool, in particular a setting tool for fastening elements, which can also be a powder—operated working tool, comprising a device body, which has a cylindrical recess and a piston chamber communicating therewith for receiving a piston; an impact plate, which is arranged opposite the cylindrical recess and can be moved towards or away from the device body, and a packing sleeve mounted in the cylindrical recess and which can be moved out of the cylindrical recess.
The packing sleeve is carried by the device body and not by the impact plate so that the impact plate has a lesser mass. It can therefore be displaced more lightly and faster assisting in improved operational control of the working tool. High forces are no longer required for driving the impact plate thus saving energy. Furthermore, the drives for driving the impact plate can be configured more simply resulting in costs savings and weight economies.
According to a further embodiment of the invention, the packing sleeve can be urged by a spring force against the impact plate such that tolerances inter alia can be balanced in the transmission system driving the impact plate.
According to an embodiment of the invention, the central axes of the piston chamber and the cylindrical recess are inclined towards each other, whereby the inclination is preferably 90°. In this fashion, the well—known side—fire concept can be realized in a working tool of the aforementioned type. This has the advantage inter alia that the cartridges can be transported along a track to the respective firing position, which lies parallel to the central axis of the piston chamber; in other words, parallel to the setting direction.
It is, however, also possible to arrange the central axes of the piston chamber and the cylindrical recess coaxial to each other. The cartridge supply system in the respective firing position would then come to be vertical to the setting direction of the working tool.
According to a very advantageous further embodiment of the invention, the packing sleeve has adjusting surfaces, by which it can be urged against the impact plate by a gas pressure, which builds after firing of the loaded cartridge.
Accordingly, a closure is created for the cartridge bearing, which generates the sealing force. The very high gas pressure occurring in the cartridge bearing or in the packing sleeve upon firing of a cartridge thus pushes the packing sleeve against the impact plate and does this with such power, that no gas can escape in the zone between the packing sleeve and the impact plate. When this is done, the sealing force is so high that even a thin walled blister cartridge is held such that it can withstand the enormous gas pressure of several 1000 bar.
The lower surface of the packing sleeve can be used as the adjusting sleeve for the gas pressure, which is always at a distance from the floor of the cylindrical recess.
Preferably, the packing sleeve is provided peripherally with seals to provide adequate gas sealing in the gap zone between the packing sleeve and the inner wall of the cylindrical recess.
When this is done, according to the embodiment of the invention, the packing sleeve can have a peripheral recess, at its end facing away from the impact plate, running in its facial surface for forming such a thin external wall section that it can be urged against the inner wall of the cylindrical recess by the very high gas pressure occurring in the cartridge bearing upon firing a cartridge.
Alternatively or in addition, the known FEY rings can be provided between the packing sleeve and the inner wall of the cylindrical recess. These FEY rings can be situated approximately in an external peripheral groove of the packing sleeve or in a peripheral groove on the inner wall of the cylindrical recess.
According to another embodiment of the invention, the packing sleeve can also be screwed into a so-called thread in the cylindrical recess. This thread is so wide that the elastically mounted packing sleeve can be pushed into its axial longitudinal sense to press elastically against the impact plate. In this manner, an initial sealing between the front edge of the packing sleeve and the impact plate can be obtained while at the same time a sufficient sealing in the zone of the thread is possible. After firing the cartridge present in the firing chamber, the packing sleeve is urged against the impact plate by the very high pressure building up, whereby it is compressed in the zone of the thread in this direction by the flanges of the increasing thread in this zone to seal at that point.
According to yet another development of the invention, the packing sleeve can be screwed into the cylindrical recess using a threaded insert. In this instance, a specially shaped thread is present on the external periphery of the packing sleeve and on the inner wall of the cylindrical recess, whereby a corresponding threaded insert is screwed into this specially shaped thread. This threaded insert is a coil made of flat strip material, wherein the width dimension of the flat band is in the radial sense of the coil. A satisfactory seal is also maintained in the zone between the packing sleeve and the cylindrical recess, when the packing sleeve is displaced in the one or the other direction relative to the device body.
According to another development of the invention, the packing sleeve is provided with an outer peripheral flange, wherein a compression spring is arranged between the outer peripheral flange and the device body. The resilient mounting of the packing sleeve in the cylindrical recess can be obtained in a simple fashion by virtue of these means. The compression spring is compelled to push out the packing sleeve from the cylindrical recess, wherein it is prevented in that the packing sleeve runs up against a stop that is present in the cylindrical recess. The aforementioned thread or an inner flange on the inner wall of the cylindrical recess is gripped by a flange on peripheral edge of the packing sleeve, which faces outward. The spring force of the compression spring is selected such that a good initial seal between the external front zone of the packing sleeve and the impact plate is maintained, when the impact plate is displaced in the direction towards the packing sleeve or in the direction towards the device body.
Naturally, the packing sleeve could be mounted in the cylindrical recess such that it can be easily tipped about its central axis to compensate for incorrect positioning between the impact plate and the device body. The packing sleeve can have an outer peripheral bulge at its end facing towards the device body, said bulge being configured convex in a plane receiving the central axis of the packing sleeve. This outer peripheral bulge could be connected in one piece to the packing sleeve or could be inserted therein and receive an elastic seal ring.
According to a further embodiment of the invention, the impact plate is a section of a solid closed ring, in whose annular plane the central axis of the cylindrical recess lies.
As a result, a very simple and stable closure part is obtained, which can sustain the closure forces of several tons. It is statically advantageous that the device weight is not prohibitive and that expansions continue to be tolerated. Preferably, the closure ring can be combined with a gas conduit for the powder exhausts that escape from the cartridge holder, which is vertical to the axis of the device.
The closure ring can be displaced back and forth for opening and closing the cartridge holder or the cylindrical recess and especially in the axial direction of the packing sleeve or the cylindrical recess. In the closed seal position, the seal ring is held by a bar that comes to rest between the device body and the seal ring. This bar is situated on the side of the device body situated radially opposite to the cylindrical recess. The bar can be led into the said zone between the seal ring and the device body or can be rotated thereinto.
In an embodiment of the invention, the combustion—operated working tool has an adjusting member on the muzzle side and can be displaced relative to the device body, said member being used to control the sealing mechanism for the impact plate such that the displacement mechanism for the impact plate moves towards the device body when the adjusting member is displaced towards the device body and the impact plate moves away from the device body, when the adjusting member is again removed from the device body. Inasmuch, the operation of the working tool can be controlled in a simple fashion using the contact/removal movement.
Furthermore, in another embodiment of the invention, it is possible to transport cartridges into the zone between the packing sleeve and the impact plate as a factor of the displacement position of the adjusting member; that is, to bring it into the firing position or out of the firing position. If the adjusting member is displaced in the direction towards the device body, an adjusting mechanism could be pre-biased, which then would guide the spent cartridge out of the firing position and move the next cartridge into position, after the adjusting member is moved far enough away from the device body and the packing sleeve has moved far enough away from the impact plate.
Blister cartridges can be used which are connected to each other in a belt. This makes easy transport of cartridges to the firing position or away from same possible.
Preferably the belt is configured such that the blister cartridges protrude from only one side of the belt and the other flat side of the belt rests on the impact plate. The back of the belt can be provided with an electrically conducting foil that serves as the counter-electrode to fire the cartridge by an electrical spar between an anode and the counter-electrode. The anode could be situated in the impact plate.
A further embodiment of the invention provides that the facial surface of the packing sleeve facing the impact plate has a peripheral, stub-like projection, which extends axially and, viewed radially, lies within. In addition, the impact plate can also have a peripheral groove for receiving the stub-like projection.
The objective is to achieve a maximally high initial tightness between the packing sleeve and the impact plate, especially when using blister cartridges, even in low gas pressure and low contact pressure. This high initial tightness is made possible by deformation of the blister foil. The deformation is made using the smallest possible stub-like projection or the smallest possible blade to keep the necessary pressing force low. Provision is made to guide the packing sleeve to a stop and to keep the blade height so minimal that the blade cannot penetrate through the foil such that the foil of the blister cartridge is not perforated by the very high closing force due to the high gas pressure occurring. The stop is made on the foil in a level zone of the face of the packing sleeve. This has the advantage that the tolerances can more easily be maintained because only tow small dimensions are involved. It must also be noted, that the support zone on the foil is large in comparison to the thickness of the foil. As a result, extrusion of the foil under high closure force can be prevented.
According to a further embodiment of the invention, the face of the packing sleeve facing the impact plate lies parallel to the impact plate and the otherwise level impact plate has a peripheral, stub-like projection situated opposite said face.
A relatively high initial tightness is achieved by virtue of this stub-like projection on the impact plate even in low gas pressure and low contact pressure. Naturally, it must be assured that the stub-like projection does not sever the blister strip foil when it penetrates into the back of the cartridge belt.
Yet another embodiment of the invention resides in the fact that the face of the packing sleeve facing the impact plate is parallel thereto and the otherwise level impact plate has a truncated conical protrusion, which projects into the packing sleeve, when the sleeve presses against the impact plate. The inner peripheral edge of the packing sleeve, situated opposite to the impact plate does not contact the peripheral surface of the circular disk-like projections, which run inclined towards the axial sense of the packing sleeve, such that, in between, the blister foil of the cartridge strip is crushed, when the packing sleeve is moved against the impact plate; nevertheless, no severing occurs. A relatively high initial tightness is obtained at even low gas pressure and low contact pressure.
In a further embodiment of the invention, the face of the packing sleeve facing the impact plate can lie parallel to the packing sleeve and the otherwise level impact plate can have a circular disk-like projection, whose peripheral edge lies opposite to the inner edge of the packing sleeve. If the impact plate and the packing sleeve move towards each other, the peripheral edge can penetrate into the plastic foil of the blister cartridge and contribute to a good sealing action without severing the plastic foil.
The exemplary embodiments of the invention will be discussed with reference to the drawings, wherein:
A first exemplary embodiment of the invention will be described in detail in the following with reference to
The setting tool according to
An impact plate is arranged opposite to the open end of the cylindrical recess 5, which can be moved towards or away from the device body 1. Thus, the impact plate 8 is mounted displaceably in the longitudinal sense of the cylindrical axis 6 or the cylindrical recess 5. As can be seen in
A packing sleeve 12 is inserted into the cylindrical recess 5, which is displaceable longitudinally to the cylinder axis 6. The cylinder axis 6 of the packing sleeve 12 is coaxial with it. The packing sleeve 12 is displaceable inserted into a threaded ring 13, which in turn is screwed with its external thread into an internal thread of a cavity present in the device body 1. At the end of the packing ring facing towards the device body 1, a peripheral flange 14 is screwed onto it externally. The peripheral flange 14 grips around the threaded ring 13 to prevent the packing sleeve 12 from falling out of the cylindrical recess 5. At its end facing towards the impact plate 8, the packing sleeve 12 has a further peripheral external flange 15. A compression spring 16 is arranged between this external flange 15 and an open surface of the threaded ring 13, which is compelled to urge the packing sleeve 12 in the direction of the impact plate 8. As a result, the packing sleeve 12 cannot be urged out of the cylindrical recess 5 because the threaded ring 13 stands in the path of the peripheral flange 14.
If the closure ring 8a is in the position shown in
Piston rings 18, so-called FEY rings, encompass the packing ring 12 and are situated in a peripheral internal groove 19 of the threaded ring 13. Using these FEY rings, the gap zone between the packing sleeve 12 and the inner wall of the threaded ring 13 is sealed, when the high pressure forms inside the packing sleeve 12 (cartridge holder or combustion chamber) as the result of the firing of the blister cartridge 10.
A plate 20 is arranged on the floor of the cylindrical recess 5, said plate having perforation openings 21 in the direction facing the communication conduit 7 for creating a restriction point.
For firing a blister cartridge 10 present in the firing position, an insulator 22 is provided in the impact plate 8, in which an anode 23 is arranged, with the aid of which a spark can be generated through a channel 24 between the anode 23 and an electrically conducting foil 25, said foil being arranged on the back of the belt 9. As a result of the occurrence of the spark on the back of the belt 9, the electrically conducting foil 25 melts and the firing charge 26 present in the blister cartridge 10 is fired, which in turn fires the propellant charge 27 present in the blister cartridge 10.
The closure ring 8a is locked to prevent the impact plate 8 from being moved away from the device body 1 at the time of firing the propellant charge 27. For this purpose, a closure bar 28, which can be seen in
Both the shifting movement of the closure ring 8a and the approach and departure of the blister cartridges 10 into the firing position and the movement of the closure bar 28 can be brought into alignment with the placement or removal of the working tool on or from the object, respectively.
As can be seen in
A second exemplary embodiment of a working tool according to the invention is shown in
The blister cartridge 10 is opened by a pin 3a shortly after its firing, said pin can also be substituted by a blade after it has begun to expand. This pin or blade 3a, retracts from the trailing end of the driver piston 3 and protrude through the passage opening 7. The lack of seal of the needle in the direction of the driver piston 3 should be minimal. Therefore, the powder from the propellant charge seals the gap 7a for the needle 3a to the cartridge space. At the transition from the needle 3a to the driver piston 3 and at the external edge of the driver piston 3, helical chambers 3b are provided, which prevent any passage of powder grains and passage of gases.
According to
Yet a further possibility for sealing the gap between the packing sleeve 12 and the inner wall of the cylindrical recess 5 is shown in
As already stated, a certain initial seal should be present even with low gas pressure and low contact pressure, upon firing a blister cartridge 10 present in the firing position. This is also advantageously obtained by deformation of the blister cartridge foil. This part of the contact pressure can thus be maintained low by minimizing the deformed foil surface. As a result, the deformation occurs with the smallest possible cut. The blister cartridge foil is not perforated by the very high closing forces at high gas pressure since the packing sleeve 12 runs up to a stop and the blade height is kept so low that the blade cannot penetrate the foil. The stop occurs on the foil in a flat zone. The tolerances can thus be more easily respected since only two small dimensions are involved. Also, the contact zone on the blister cartridge is large in comparison to the foil thickness. In this fashion, extrusion of the foil under high closing force is prevented.
A sufficiently large gap is provided on the side facing away from the seal for the action of the sealing zones in the vicinity of the blister cartridge foil to have effect such that any gases flowing out cannot generate any force for opening the packing sleeve 12. As a result, the packing sleeve is constantly urged by the combustion gases of the blister cartridge 10 in the direction of sealing.
A further embodiment of the face of the packing sleeve facing the impact plate 8 is represented in
In the case of the exemplary embodiment according to
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| 102 59 772 | Dec 2002 | DE | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20040226975 A1 | Nov 2004 | US |
