The present invention relates to a staple gun for driving staples into a workpiece, which gun comprises a frame, arranged in which is a driver, which can be conveyed in an up and downward movement and which in the downward movement executes a drive stroke, in which a staple is driven, and which by means of an activation member can be conveyed in the upward movement to a highest height, at which the activation member releases the driver for execution of the drive stroke, and which driver is coupled to a first end of an elongated elastic member, which is tensioned when the driver is conveyed in the upward movement for execution of the drive stroke, and which is in engagement at a second end to a bearing pin arranged to the frame as well as a first breakpoint pin placed between the bearing pin and the driver at a first distance from the bearing pin and around which the elastic member is bent and tensioned when the driver is conveyed in the upward movement as well as a second breakpoint pin placed between the driver and the first breakpoint pin at a second distance from the bearing pin and arranged so that it can be conveyed between a first position, in which it does not engage with the elastic member when this is conveyed by the driver in the upward movement, and a second position, in which it engages with the elastic member when the driver is conveyed in the upward movement and tensions the member.
Staple guns of the type indicated above are common and are found in a large number of designs. Every well-stocked tool store more often than not offers several designs of such guns for sale.
Depending on the material into which a staple is to be driven, the degree to which the elastic member needs to be tensioned varies when the driver has been conveyed to its highest position. This means that when a great force is required, the elastic member must be strongly tensioned, while when a smaller force is required, the member can be tensioned less. When a great force is required, this has been accomplished by the elongated elastic member being made thick and thereby strongly tensioned and when a smaller force is required, said member has been made thin. Since the force is produced by bending the member around a breakpoint pin and since the upward movement of the driver is not varied, the tensioning is the same regardless of whether a great or small force is required. This means that when a workpiece requiring low force is exposed to the force from a staple gun with a powerfully designed member, the workpiece easily becomes deformed by the impact of the driver against the workpiece, which, if the workpiece is clearly visible, is often perceived as aesthetically objectionable When a staple gun with a weaker member is used for a workpiece that requires high force, it occurs that the staple is not driven sufficiently into the workpiece, which can mean that the object that one intends to attach to the workpiece is not attached satisfactorily.
These disadvantages have been overcome in more expensive staple guns such that a second breakpoint pin has been introduced, which can be conveyed between an active position in which the elastic member is bent around the pin, and an inactive position in which the pin does not cooperate with the elastic member. With such a solution it has been achieved that the staple gun can be set in various impact force positions and thereby avoid aesthetically disturbing impact marks in the workpiece or poor driving of the staple. However, it has not been possible to vary the impact force in any of these previous staple guns in such a way that the gun has been able to be used for material where a very small force is required and a material where a large force is required.
The present invention provides a staple gun in which said problem is solved by a staple gun of the aforementioned type, which is characterised by that the first distance at which the first breakpoint pin is placed from the bearing pin is related to the drivers highest height of the upward movement as 1.6-2.0:1.
The invention is further characterised by that said ratio is 1.7-1.9:1.
The invention is characterised still further by that said ratio is 1.8:1.
The invention is further characterised by that the second distance at which the second breakpoint pin is placed from the bearing pin is related to the highest height of the upward movement as 3.1-3.7:1.
In addition, the invention is characterised by that the last-named ratio is 3.3-3.5:1.
Furthermore, the invention is characterised by that the last-named ratio is 3.4:1.
Finally, the invention is characterised by that the second breakpoint can be conveyed to a position in which it makes contact with the elastic member when the driver is raise half of the distance h.
The invention is to be described in detail below with reference to the enclosed figures, in which:
With reference to
With reference to
By placing the first pin at a distance a from the pin 18, where the ratio a to h is 1.6-2.0:1, it is achieved that the elastic member is only tensioned to such a degree that unnecessary force is not brought against the workpiece when a staple is driven into this. It has proved to be especially advantageous if the ratio is made in the range of 1.7-1.9:1 and the ratio 1.8:1 has proved to be of great value.
For cases where strong tensioning is required, it has proved that such an advantageous tensioning is achieved if the second breakpoint pin is placed at a distance b from the pin 18, where the ratio b to h is 3.1-3.7:1 and the ratio 3.3-3.5:1 has proved especially valuable and the ratio 3.4:1 has proved to be very valuable.
By placing these pins in any of the ratios indicated above, it is achieved that a staple gun with a particularly variable adjustment of the impact force positions is accomplished. Further increased variation is achieved if the second pin is placed in an intermediate position where the elastic member comes into contact with the pin when the driver is raised by 0.4-0.7 h.
The invention is not limited by the above description, but is limited only by the following claims.
Number | Date | Country | Kind |
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1200718-3 | Nov 2012 | SE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/SE2013/000167 | 10/31/2013 | WO | 00 |