GB2440591A

GB2440591A - Method of driving a fixing element into a workpiece

Info

Publication number: GB2440591A
Application number: GB0516292A
Authority: GB
Inventors: Bryan Nigel Victor Parsons
Original assignee: Individual
Current assignee: SEARLE, ROY
Priority date: 2005-08-09
Filing date: 2005-08-09
Publication date: 2008-02-06
Also published as: GB0516292D0

Abstract

A fixing element is driven into a workpiece (36, fig 1) in a number of steps. The steps include providing a fixing element 52, driving the fixing element into the constructional element, providing a covering element 55 for the top of the fixing element, and driving the covering element into the constructional element simultaneously with the fixing element. As a result the covering element conceals the top of the fixing element in the constructional element. An adhesive or filler may be applied to the workpiece after the fixing element and covering element have been driven into the workpiece. The covering element may be a cap mode of wood such as hardwood, birch, or beech as a thin veneer, and may have dimensions exceeding those of the top of the fixing element.

Description

Nail gun nail caps The present invention relates to devices for driving

fixing elements into constructional materials, such as nails into wood, and in particular to a nail gun for use such as the construction of pallets and crates, fixing of floor boarding, manu1cture of furniture and fixing of trim and architraves.

When using machines of the above type, the depression left in the material when the nail is driven to the required depth can be unacceptably unsightly. To improve the finish the depressions might be filled with a wood-filler which could require further dressing when cured. This is a labour intensive operation which increases the cost of the process. It is the object of this invention to provide a means to fill the holes and depressions formed during the nailing process simultaneously with the nailing operation.

According to the current invention there is provided a gun device for driving a fixing element such as a nail or screw into a constructional element, comprising: a magazine for containing one or more fixing elements; a driving mechanism for driving the fixing element, taken from the magazine, into the constructional element; a supply of nail cap elements; so that in operation a nail cap element is positioned between the driving mechanism andthe..fixini.

element and is driven into the constructional element so that the nail cap element hides the top of the fixing element and provides an improved appearance.

According to a preferred embodiment the nail cap elements are previously attached to the fixing element by adhesive means and the body of the gun device is adapted to convey the fixing elements and the attached nail cap elements to the driving mechanism for fixing to the constructional element.

Preferably the nail cap elements are made from a matching material to the constructional element so that nail cap elements might be painted, or stained to match the constructional element. When the constructional element is wood, the nail cap elements might be made from fine grained birch, beech or hardwood veneer, to withstand the pressure between the driving mechanism and the fixing element, without splitting of disintegraling.

Preferably the dimensions of the nail cap element will exceed the dimensions of the top of the fixing element so that the nail cap element is forced into the hole formed in the constructional element by the passage of the top of the fixing element and form a tight fit.

For the case where the fixing element has a circular top, the diameter of the nail cap element would preferably be 10% larger than the fixing element circular top.

Where the fixing element has a rectangular top and the fixing elements are stored abutting one another, the width of the nail cap element is preferably 10% wider than the width of the fixing element, where the width is defined perpendicular to the direction of the abutting stack.

According to a further preferred embodiment, a quantity of glue or filler might be introduced to the nail cap element to form a bond between the nail cap element and the constructional surfuce.

According to a further embodiment the nail cap element might be tapered so that the nail cap element might more easily enter the hole in the constructional element and wedge more tightly when driven deeper.

Preferably, for wooden nail cap element for the case of the abutting rectangular fixing elements, the nail cap element might be attached as a continuous veneer across a number of fixing elements in a stack so that the grain of the wooden nail cap element is perpendicular to the direction of the stack and breaks off easily under the action of the driving mechanism as the fixing element shears from the stack. So that the fixing element driven into the constructional surface has a portion of the nail cap still attached and hiding the fixing element top.

According to a further embodiment the tip of the driving mechanism that contacts the nail cap element is profiled to hold the nail cap element in place whilst driving the fixing element into the constructional surface.

According to one preferred design option the tip of the driving mechanism is made concave to prevent nail cap element from being squeezed out of the edges.

According to an alternative design option the tip of the driving mechanism is made deliberately rough with sharp apices to engage with the material of the nail cap element and prevent relative sideways motion during the fixing process.

According to further aspect of the invention the action of the drive pin might form or trim the nail cap element at the moment of firing.

An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings, in which:-Figure la-lb show the basic elements of a nailgun in accordance with this invention; Figure 2a-2b shows a section of nails formed into belt for loading into a nailgun with the attached nail caps; Figure 3a-3b shows a section of nails formed into a stack with the attached nail caps; Figure 4 shows the modified tip of the nail driver in accordance with this invention.

Figure 1 shows the important features of a nailgun, where nails 43 are formed into a strip to be fed through slot 45 in the gun barrel 35 from a magazine (not shown) held by mounting holes 48. The drive pin 42 is powered by piston 41 by gas pressure on its upper surface, regulated by a trigger mechanism (not shown). A second interlocking trigger mechanism is attached to the foot 44 so that in order for the nailgun to operate both trigger mechanisms must be activated. This is a safety feature and prevents accidental firing of the nailgun. The foot 44 is spring loaded to the extended position shown in the figure lb. In order to activate the trigger mechanism the foot 44 must be depressed as shown in figure ic so that the end of the nailgun barrel 35 is brought close to the wooden block 36. When the two trigger mechanisms are activated the drive pin 42 moves down through orifice 47 in barrel 35 and contacts one of the nails 43, together with the nail cap 62 (figure 3), and drives it into the wooden block 36. The nail cap 62 is pressed into the hole so formed and hides the nail 43 from sight.

Figure 2 a-b shows a string of round nails 52 joined by wires 54 welded at regular intervals to form a belt to be fed into a nail gun. The nail caps 55 shown separate in figure 2a and adhesively attached figure 2b are attached during the manufacturing process. The adhesive that joins the nail caps 55 to the nails 52 has a high compressive modulus to prevent lateral squeezing of the adhesive during the fixing of the nail 52. The adhesive has to be strong enough to prevent accidental dislodging of the nail caps 55 from the nails 52 whilst handling the nail belt. In operation the wires 54 that support the nails 52 are severed. The nail cap 55 is substantially 10% larger in diameter than the nail 52 top and the drive pin 42 (which for these nails would be circular in section).

Figure 3a & 3b show a stack of nails 72 lightly bonded together to form a nail strip 43 to be fed into a nail gun. The nail caps 62 are formed as a complete strip bonded to the top of the nail strip 43 during manufacture. The nail caps 62 are formed of beech or birch as a thin veneer with the grain of the wood orientated across the nail strip 43, so that as the drive pin 42 detaches the end nail 72 it severs a portion of the nail cap 62 across the grain of the wood and drives both the nail 72 and nail cap 62 into the surface of the wooden block 36. The width of the nail cap 62 is about 10% wider than the width of the nail strip 43 to ensure a tight fit of the nail cap into the hole formed by the top of the nail 72. The adhesive supporting the nail cap 62 to the nail strip 43 might melt during the process of firing the nail 72 and help to fix the nail cap 62. Alternatively adhesive might be applied directly to the surface of the wooden block 36 and be carried to the interface of the nail cap 62 and the hole.

Figure 4 shows the tip of the drive pin 42 modified with indentations 49 to ensure that the nail cap 62 remains in place between the nail 72 and the drive pin 42 during the firing process.

The softer material of the nail cap 62 compared to the drive pin 42 ensures that the surface of the nail cap 62 defonns and engages with the profile of the drive tip indentations 49, to prevent lateral movement.

Various modifications might be made without departing from the invention. For example nails with different head shapes might be employed, such as crescent shaped, with corresponding changes to the nail cap design.

Claims

CLAIMS

1. A method of driving a fixing element into a constructional element, the method comprising the steps of: providing a fixing element; driving the fixing element into the constructional element; providing a covering element for the top of the fixing element; and driving the covering element into the constructional element simultaneously with the fixing element whereby the covering element conceals the top of the fixing element in the constructional element.

:. 10
2. A method according to claim I and including the further step of applying a substance to the surface of the constructional element so as to be positioned * S..

between the fixing element and the constructional element after the fixing element and the associated covering element have been driven into the constructional element. * . *5S S. ** * . . * S
3. A method according to claim 2, wherein the substance is selected from adhesive and filler.
4. A method according to any preceding claim, wherein covering elements are attached to the fixing elements prior to the covering elements and the associated covering elements being driven into the constructional element.
5. A method according to claim 4, wherein the covering elements are secured to the fixing elements by means of an adhesive which has a compressive modulus sufficient to prevent lateral squeezing of the adhesive when a fixing element and associated covering element are driven into the constructional element.
6. A method according to claim 5, wherein the adhesive is selected to melt when a fixing element and associated covering element are driven into the constructional element.
7. A method according to any preceding claim, wherein the covering element is tapered so as to facilitate entry into the constructional element. *S.. * * ***S

:.
8. A method according to any preceding claim, wherein the dimensions of * *:. the covering element exceed the dimensions of the top of the fixing element * * ** whereby the covering element is forced into a hole formed in the constructional *S*.

element by the passage of the fixing element.

9. A method according to claim 8, wherein the covering elements have a diameter which is substantially 10 percent larger than the diameter of the fixing elements.

10. A method according to claim 8, wherein the covering elements have a width which is substantially 10 percent larger than the width of the fixing elements.

11. A method according to any preceding claim, wherein a driving mechanism having a profiled tip is provided whereby the tip holds the covering element in place while driving the covering element into the constructional element.

12. A method according to claim 11, wherein the tip is concave.

13. A method according to claim 11, wherein the tip is roughened and provided with sharp apices to engage the covering element and inhibit lateral movement thereof. :. 10

14. A method according to claim 11, 12 or 13, wherein the tip is profiled to * S..

trim the covering element to a predetermined size as the covering element is * .;: driven into the constructional element. **S. *IS

:., 15 15. A method according to any preceding claim, wherein the covering elements are selected to match with the material of the constructional element.

16. A method according to claim 15, wherein the covering elements are painted or stained to match with the material of the constructional element.

17. A method according to claim 15 or 16, wherein the covering elements are made of wood veneer.

18. A method according to claim 17, wherein the covering elements are selected from fine-grained birch, beech or hardwood.

19. A method according to claim 18, wherein the grain of the wood is selected to extend transversely of the fixing element.

20. A method of driving a fixing element into a constructional element substantially as hereinbefore described with reference to the accompanying drawings. S. * S * *.* * 555 * S * 55.

S S. * 5*5 5. I... * SI.. *5 * 5 5 5