Arrangement in apparatus for mechanical nailing

Device in a mechanical nailing apparatus including a nail holder to support and guide a nail into position for nailing by means of a nail driver. The device is especially designed for nails (51) which, after being nailed, has at least one laterally expanded anchoring portion (52). The inner cavity of the nail holder (55, 56) intended to receive the nail defines, along part of the nail (51), a guide seat (53) of non-circular section adapted to co-operate complementarily with a guide portion (52) on the nail (51) such that the nail, as it is carried into position for nailing, is given a definitely fixed angle of orientation about its longitudinal axis relative to the nail holder. By positioning of the nail holder, i.e. the nailing apparatus, into a suitable angle for anisotropic materials, e.g. the fibre direction in wood, an expansion nail may be nailed in the angular position where the nail will reach maximum gripping power.

The present invention relates to a means for orienting the turning angle of 
a nail about its longitudinal axis before driving in the nail by means of 
an apparatus adapted for mechanical nailing. Such an apparatus includes, 
on one hand, a nail holder holding the nail in position for nailing and, 
on the other hand, a nail driver for driving in the nail. 
Existing apparatuses for mechanical nailing or nailing by machine 
completely lack means for turning or orienting the nail into a certain 
desired angular position about its longitudinal axis and holding the nail 
in this position prior to nailing. This is a great inconvenience when it 
is a matter of mechanical nailing with expanding nails, especially such 
expansion nails which, after nailing, exhibit one or more anchoring 
portions, i.e. portions of the nail expanded or split out from the shaft 
of the nail inside the material. Especially when using expansion nails in 
non-isotropic materials it is a great advantage to orient the nail into 
such an angle of orientation relative to the structure of the material 
that maximum gripping power is obtained. 
A common such case is the use of expansion nails according to the Swedish 
Pat. No. 7703167-2 for nailing in wood or joining of wooden details. A 
portion of this expansion nail, situated adjacent the point thereof, is 
deformed outwardly towards both sides. It is obvious that such a nail will 
take a better hold in the wood and thus attain much greater gripping power 
if the expanding portions extend at right angles to the wood fibre 
direction than if they would extend in parallel with the fibre direction. 
By this invention a positioning or orientation means is provided for 
orienting a nail into such a position of rotation that the nail gripping 
power attains a maximum after being driven into anisotropic materials. 
According to the invention this great advantage is achieved in a most 
simple, cheap and reliable manner in that the inner, nail-receiving cavity 
in the nail holder defines, along a portion of the nail, a guide seat of 
non-circular cross-section adapted to cooperate complementarily with a 
guide portion of the nail such that the nail will be held in a definitely 
fixed angle of orientation about its longitudinal axis relative to the 
nail holder. 
In preferred embodiments of the invention the guide seat of the nail holder 
is adapted to guide portions of the nail comprising a non-circular nail 
head, a bulged portion of an expansion or rivet nail or a wedge or 
chisel-shaped point. In the latter case the guide seat is an edge seat in 
the nail holder. 
An advantageous means is realized if the nail holder consists of at least 
two jaws which are movable outwards from the nail and away from each other 
and are kept resiliently pressed against each other. By this protruding 
nail portions such as the nail head and bulges of a rivet nail may be 
pushed through the entire nail holder by the nail-driver.

FIG. 1 shows an expansion nail 1 with an anchoring portion 2. The nail is 
driven into the material 3 to fasten a clip 4, for instance for wiring on 
a wall. 
FIG. 2 shows an expansion nail 5 according to the above-mentioned Swedish 
patent, as used for joining of two wooden parts 7 and 8. The nail includes 
an expansion portion 6 extending outwards on either side of the nail at 
right angles to the wood fibre direction. 
FIG. 3 shows a nail holder in which a nail 30 of the type shown in FIG. 1 
lies ready for nailing. The nail head 31 constitutes the guide portion and 
coacts with a guide seat 32 in the nail holder in a manner to be described 
in greater detail below. The point of the nail 30 is designated by 33. It 
abuts against, or lies close to the material 34 into which it is to be 
driven. 
The nail holder consists of two spring-loaded cheeks or jaws 35 and 36 
which are movable in outward direction. Above the nail head 31 is a nail 
driver 37 for driving the nail into the material 34. When the nail driver 
37 drives the nail 30 into the material 34 the point 33 of the nail 
presses aside the jaws 35, 36 and penetrates into the material. After the 
nail has come into contact with the material it cannot turn about its 
longitudinal axis but is non-rotatably oriented relative to the material. 
As the driving-in operation continues the nail head 31 moves downwards 
while carrying apart the spring-loaded jaws 35 and 36 until the nail comes 
outside the jaws and is fixed in position. The nail 30 may, for instance, 
fasten a clip designated by 39. 
FIG. 4 shows a cross-section of the device on line IV--IV in FIG. 3. From 
the figure appears how the expansion nail 30 has been brought into the 
desired angular position about its longitudinal axis. The nail head 31 is 
defined by two straight edges and two circular arcs situated therebetween. 
The nail head will thus constitute the guide portion of the nail with 
which the complementary shaped guide seat 32 of the nail holder will 
coact. The guide seat 32 is placed straight opposite the nail head 31 when 
the nail is in position for nailing and leaves a certain play for the nail 
head, i.e. for the guide portion 31 of the nail. 
The nail 30 can be carried towards its position for nailing by means of 
gravity, of a spring, of an air current or the like. During this movement 
the guide portion--the head 31--of the nail 30 is carried into the guide 
seat of the nail holder 35, 36, where it is brought into the desired angle 
of orientation. This introduction into the seat is also facilitated by 
vibrations or other movements in the nailing apparatus. The nail is then 
kept in starting position for nailing. 
FIG. 5 shows a nail holder adapted for a rivet nail 51 to the expansion 
portion 52 of which is utilized as guide portion. The jaws of the nail 
holder, designated by 55 and 56, have an inner guide seat 53 for coaction 
with the guide portion 52 of the nail 51. The material into which the nail 
is to be driven is designated by 54. The device shown in FIG. 5 
corresponds in principle to the device of FIG. 3. 
FIG. 6 shows a cross-section of the parts in FIG. 5 taken on line VI--VI. 
From the figure appears the substantially ellipse-shaped expansion portion 
52 and the corresponding guide seat 53 in the nail holder 55, 56, having a 
slight interference with the expansion portion 52. As in the device 
described above with reference to FIGS. 3 and 4, the nail 51 has been 
brought into a definite, fixed angle of orientation in the nail holder 
prior to nailing which is carried out by means of a nail driver in the 
manner described above. 
FIG. 7 shows the point of a rivet nail 71 as viewed in two relatively 
perpendicular directions. In the case shown the point 72 of the nail 71 is 
in the form of a wedge or chisel-shaped portion having two surfaces 73, 
inclined towards one another and an edge 74. The point 72 with the portion 
73, 74 constitutes the guide portion of the nail. 
FIG. 8 shows in two relatively perpendicular sections the outermost point 
of a nail holder with jaws 85, 86 and a guide seat 87 which is adapted for 
coaction with the chisel-shaped point 72, 73, 74 of the nail in FIG. 7. 
The right-hand part of FIG. 8 shows the resilient jaws 85 and 86 the inner 
lowermost portions of which consist of two angularly disposed planes 82 
which form a seat for the chisel-shaped point 72 of the nail 71. The seat 
or edge location 87 constitutes the guide seat of the nail holder 85, 86. 
When the point 72 of the nail rests in the seat 87 the nail 71 is oriented 
in the desired angle of orientation and is ready for nailing in the manner 
described above. 
It has been described in the foregoing how expansion nails according to the 
invention have been brought into a defined fixed position relative to the 
mechanical nailing apparatus. Thus, in order to produce maximum gripping 
power when driving in nails in anisotropic materials it is easy to turn 
the apparatus into the desired position relative to the material, e.g. 
with respect to the fibre direction in wood. 
In the above examples a nail holder with two jaws has been described. Of 
course it is possible to use holders having three or more jaws, to give 
the guide portion of the nail and the guide seat of the nail holder 
adapted thereto a triangular or other non-circular configuration or to 
carry out other modifications within the scope of the appended claims 
without departing from the inventive idea.