U.S. patent number 3,889,450 [Application Number 05/305,419] was granted by the patent office on 1975-06-17 for methods and apparatuses for making strips of nails for use in nail driving tools.
This patent grant is currently assigned to Helsingborgs Spikfabriks AB. Invention is credited to Claes-Goran Staffan Andersson, Claes Otto Sigfrid Danielson, Hans-Ake Christian Gram.
United States Patent |
3,889,450 |
Danielson , et al. |
June 17, 1975 |
Methods and apparatuses for making strips of nails for use in nail
driving tools
Abstract
The invention relates to an improved method of making strips of
fasteners disposed between and adhesively bonded to at least two
opposed parallel tapes, especially simplifying guiding and gripping
of the fasteners during operation such that the fasteners, when in
the tape applying station, are properly oriented with respect to
their angle of inclination and, for the production of strips of
fluted fasteners, also with respect to the angular position about
their longitudinal axis, all in a manner that in a substantial
degree facilitates automatic production of such strips, and by
using relatively simple equipment capable of giving high
performance and eliminating operational breakdown.
Inventors: |
Danielson; Claes Otto Sigfrid
(Malmo, SW), Andersson; Claes-Goran Staffan (Raa,
SW), Gram; Hans-Ake Christian (Helsingborg,
SW) |
Assignee: |
Helsingborgs Spikfabriks AB
(Helsingborg, SW)
|
Family
ID: |
23180701 |
Appl.
No.: |
05/305,419 |
Filed: |
November 10, 1972 |
Current U.S.
Class: |
53/591; 156/552;
414/793.2; 156/301; 414/788.3 |
Current CPC
Class: |
B65B
15/04 (20130101); Y10T 156/1095 (20150115); Y10T
156/1734 (20150115) |
Current International
Class: |
B65B
15/04 (20060101); B65B 15/00 (20060101); B65b
027/10 () |
Field of
Search: |
;53/3,196,198R,200
;156/301,552 ;214/6D,6DS,6F,6FS |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Assistant Examiner: Sipos; John
Claims
We claim:
1. Apparatus for continuously producing strips of spaced fasteners,
comprising in combination first guide means, means for continuously
aligning individual fasteners in a row with the fasteners extending
generally parallel to and spaced from each other, means for moving
said aligned fasteners along a path determined by said first guide
means tape applying and securing means for applying tape means in
engagement with said aligned fasteners in the longitudinal
direction of the row and for securing together said tape means and
aligned fasteners for producing a web of fasteners fixed in space
relationship by said tape means, means for moving said web along a
path from said tape applying and securing means, to a cutting
means, said cutting means cutting said moving web into individual
strips, second means for moving said individual strips to a
stacking station, the apparatus further comprising strip catching
and stacking means located at said stacking station for catching
each of said strips received from said second means and stacking it
in a stack at said stacking station, said strip catching and
stacking means being adapted to selectively release said strips and
turn each released strip around an axis parallel with the
longitudinal axis of said strip to stack every second strip on its
right side and the other strips on their left side in said stack,
wherein said strip catching and stacking means includes second
guide means receiving said strips from said second means moving
said strips, said second guide means being movably mounted to move
between a first position supporting said strips within said second
guide means and a second position wherein said strips are released
to fall by gravity from said second guide means, and third means
actuated by a one of said strips received in said second guide
means and moving said second guide means respectively between first
and second positions.
2. Apparatus as defined in claim 1 wherein said third means
includes a switch which is activated by contact with a one of said
strips received in said second guide means and a double-acting
cylinder connected to said second guide means and operating in
response to signals received from said switch.
3. Apparatus as defined in claim 1 further comprising a pair of
electromagnetic means rotatably disposed below said second guide
means to be, in a first position, in the path of fall of said
strips released from said second guide means, said third means,
when actuated, alternately actuating a one of said pair of
electromagnetic means whereby said electromagnetic means, in said
first position catches a strip falling in said path of fall, fourth
means, actuated by said third means, said fourth means being
operatively disposed with said pair of electromagnetic means and
rotating, respectively, the one of said pair of electromagnetic
means holding a strip through an angle of 90.degree. away from a
medial plane of said second guide means to a second position and
then releasing said strip to fall by gravity to the top of said
stack, said fourth means, after release of said strip, returning
said electromagnetic means to said first position.
4. Apparatus as defined in claim 3 wherein said fourth means
includes a pair of cylinders operative associated with each of the
said pair of electromagnetic means and moving said electromagnetic
means, a second switch operated when said strip is rotated to said
second position, said second switch, when operated, signalling said
pair of cylinders to operate in a manner to return said
electromagnetic means to said first position.
5. Apparatus as defined in claim 1 wherein said first and second
guide means are adjustably mounted over a support base, which is
generally horizonally disposed, to be selectively disposed in a
plurality of inclined positions with respect to said support
base.
6. A device for stacking strips of fasteners fed from such
apparatus for producing strips of fasteners fixed in spaced
relationship by tape means as have guide means by which said
produced strips are guided, said stacking device comprising strip
receiving means for receiving, temporarily holding and releasing
each strip fed from said apparatus through said guide means and a
strip catching and stacking mechanism comprising rotatable
supported means for catching each strip released from said
receiving means, rotating means for turning said stacking means
substantially 90.degree. in opposite directions from a catching
position around an axis substantially parallel with the
longitudinal axis of each strip caught thereby to a stacking
position such that every second caught strip is turned on its right
side and the other strips on their left side, and means connected
to said catching means and adapted to cause said catching means to
drop said strips on a stack.
7. A device as defined in claim 6, whererin said strip receiving
means comprising separable guide members defining a guide for
receiving said strips fed from said guide means of said apparatus,
said guide members being relatively movable between a first
position supporting a strip received in said guide and a relatively
separated second position for releasing said strip and permitting
it to fall by gravity from said guide, operating means for moving
said guide, operating means for moving said members relatively to
each other between first and second positions and activating means
adapted to be actuated by each strip received in said guide between
said members and to actuate said operating means.
8. A device as defined in claim 7, wherein said activating means
includes a switch adapted to be actuated by contact with each strip
received in said guide and wherein said operating means comprises a
double-acting cylinder connected to one of said guide members and
adapted to operate in response to signals received from said
switch.
9. A device as defined in claim 7 and further comprising a pair of
electromagnetic means rotatably disposed below said guide defined
by said members, each of said electromagnetic means having a first
position close to the path of fall of said strips released from
between said members when moved apart, said activating means being
adapted, when actuated, to actuate said pair of electromagnetic
means alternatively such that each of them in said first position
catches every second strip falling in said path of fall, rotating
means actuated by said activating means and operatively disposed
with said pair of electromagnetic means to rotate, respectively,
the one of said pair of electromagnetic means holding a strip
through an angle of 90.degree. away from a medial plane of said
guide defined by said members to a second position and then
releasing said strip to fall by gravity to the top of said stack,
said rotating means, after release of said strip, returning said
electromagnetic means to said first position.
10. A device as defined in claim 9, where in said rotating means
includes a pair of cylinders operatively associate with each of the
said pair of electromagnetic means for moving said electromagnetic
means between said first and second positions, a second switch
operated when said electromagnetic means are rotated to said second
position, said second switch, when operated, signalling said pair
of cylinders to operate in a manner to return said electromagnetic
means to said first position.
Description
This invention relates to a method of making strips of fasteners
fixed parallel to and spaced regular distances from each other
between tapes of paper, plastics or like material adhesively
adhered to the fasteners which are of the type having a shank with
a head at one end and a point at the other end and which are fed
from a supply, arranged in a row with the shanks parallel and the
points directed in the same sense and are delivered to a tape and
adhesive applying station to which at least two tapes are fed from
a supply of such tapes which are joined by adhesive in parallel
relationship on either side of the row of nails.
For driving nails into various materials it is previously known to
use relatively light-weight, usually hydraulically or pneumatically
operated portable tools which are loaded with strips of nails of
the above type, that is usually strips of nails comprising a row of
nails between two paper tapes adhesively adhered on either side of
the row of nails. These paper tapes hold the nails equidistantly
spaced in parallel positions and with the points directed in the
same sense. Earlier, the diameters of the nail heads were
determinative for the minimum distance between the nails in these
strips of nails, considering that the outermost nail in a strip of
nails when driven in by means of the portable tool shall go free
from the head of the adjacent nail in the strip of nails.
In such an arrangement the nails can be placed with the upper faces
of the nail heads situated in the same plane, the shanks of the
nails extending at right angles to the paper tapes adhered on
either side of the row of nail shanks. From this arrangement one
has turned to disposing the nails obliquely with respect to the
tapes adhered thereto and with the nails head located in different,
parallel and equidistant planes. A characteristic feature of this
arrangement is that the nail head overlap, the head of the first
nail in the strip of nails bearing with its edge against the shank
of the subsequent nail in the strip below the head of said nail
which in turn is disposed in a corresponding manner with respect to
the following nail, and so on in the entire strip. By this
arrangement the nails in principle can be placed with the shanks at
a distance from each other that corresponds to the distance from
the edge of the nail head to the shank of one and the same nail.
The angle between the nail shanks and the longitudinal direction of
the adhesive tapes is determined for practical reasons with due
regard to the portable nail driving tool.
For making such strips of nails it is previously known to use
continuously operating machines equipped with a conveying mechanism
which is driven continuously to convey nails from an orienting and
feed station to a tape and adhesive applying station in which paper
tapes are continuously adhered by means of adhesive to the shanks
of the continuously advancing row of nails. From this station the
continuous strip of nails formed in this manner is moved past a
cooling station in which the adhesive is caused to set, and then to
a fault detecting and strip severing station in which strip
sections of predetermined lengths are severed from the continuous
strip of nails held together by tapes adhered thereto, whereupon
the strip lengths are discharged for packing.
Prior art machines of this type are very complicated and
consequently expensive. The complicated construction of the prior
art machines is due to the difficulty of coordinating the operating
phases of the work stations in such a way that the entire operation
can be performed at a smooth rate without disturbances. If a
disturbance occurs in some station this naturally affects the
entire course of operation in the machine. Particularly sensitive
operations are that of feeding the nails to the tape and adhesive
applying station in the exact orientation necessary during the
adhering of the paper tapes to the nails, and that of holding the
nails while simultaneously moving them in a continuous motion
during the course of the tape applying operation. Moreover, the
cutting of the continuous strip of nails into predetermined lengths
and, as the case may be, ranging the severed lengths of strips of
nails for packing constitutes an operation apt to be disturbed.
The main object of the present invention is to overcome the
disadvantages outlined above by providing a method that enables
simple, undisturbed and well coordinated operations to be effected
by means of a continuously operating simple and inexpensive machine
of reliable function.
Further objects of the invention are to permit making strips of
wire nails of rectangular section (brads), which has not been
possible in the prior art machines.
To this end, the fasteners are conveyed in the ranged position from
the supply to, and are suspended in, an inclined guide so as to
depend with free inclination and with downwardly directed points,
whereby the angular position of the shanks with respect to the
plane of the guide is determined by gravity, and the fasteners are
conveyed in this position to the tape and adhesive applying station
where they are grasped in turn of order, kept the desired relative
distance apart, and fed in between the tapes likewise supplied to
said station, while the fasteners are still retained in the
inclined guide and the tapes are adhered along the row of fasteners
in parallel with the guide, whereupon the resulting continuous
strip of nails is advanced along the guide to a severing station
and cut in a known manner into predetermined lengths which are
transferred to a stacking station for packing.
According to the invention, the machine for carrying out the method
described above of making strips of nails comprises means for
orienting the fasteners into a row with the points facing in one
and the same sense and with the shanks placed in an angle of
90.degree. or less relative to the longitudinal direction of the
row, a tape and adhesive applying station for adhering said tapes
on either side of the shanks, conveying means for conveying the
fasteners arranged in said row to the tape and adhesive applying
station which includes two tape unwinding means for rolling the
adhesive tapes onto said shanks and two fixation means for holding
the fasteners in a predetermined position during the tape and
adhesive applying operation at the same time as the fasteners are
continuously advanced to a severing station which includes cutting
means for cutting the continuously fabricated strip of nails into
predetermined lengths. The conveying means is an inclined guide
which is adapted to support the row of fasteners freely suspended
with downwardly directed points during conveyance of the fasteners
up to and into the tape and adhesive applying station so that
gravity determines the angle of inclination .alpha. between the
fasteners and the guide which is adapted, in conjunction with the
fixation means, to guide the fasteners in this inclined position in
between the tapes supplied to the tape and adhesive applying
station with the fasteners still situated in the inclined guide
during adhering of the tapes to the shanks, the tape unwinding
means for rolling the tapes onto the shanks of the fasteners with
the same inclination in relation to the horizontal plane as the
inclined guide preferably being connected to the guide.
The invention will be more fully described hereinbelow with
reference to the accompanying drawings in which:
FIG. 1 in a heavily diagrammatic representation shows the method of
making strips of nails;
FIG. 2A-2F together show a plan view of a machine for making strips
of nails;
FIG. 3 is a diagrammatic perspective view of the tape and adhesive
applying station in FIG. 2B;
FIG. 4 is a longitudinal section taken on line IV--IV in FIG. 2B
and shows a nail distributing and holding wheel and a pressure
roller in the tape and adhesive applying station;
FIG. 5 shows the tape and adhesive applying station in cross
section taken on line V--V in FIG. 2B;
FIG. 6 is a horizontal section taken on line VI--VI in FIG. 5;
FIG. 7 shows the feed assembly for the strips of nails in a cross
section taken on line VIII--VIII in FIG. 2D;
FIG. 8 is a side view of the strip catching and strip stacking unit
shown in FIG. 2F;
FIG. 9 shows a strip of nails immediately before discharge thereof
from the machine.
In the nail strip making machine diagrammatically illustrated in
FIG. 1 nails are fed from a supply of randomly oriented nails in a
magazine 1 which is a known vibration feed means in which the nails
from a randomly oriented stack are oriented during discharge by
vibration caused by an electromagnetic vibration generator and
transferred to a guide 2 with the points directed downwards and
carried in this position to a conveying chute 3 which is
illustrated in the form of two parallel bars spaced apart a
distance that corresponds to the diameter or width of a nail shank.
The nails are advanced along the conveying chute 3 suspended in a
row 4 with the nail heads resting on the upper face of the chute to
a tape and adhesive applying station 5 in which a paper tape 6
having two strands of molten thermoplastic resin 7 placed on it, is
adhered to either side of the nail shanks which in this station 5
pass between two wheel and roller means advancing the nails at
correct relative distances and in correct angular position and
rolling out the tapes 6 onto the shanks of the nails at the rate at
which the row of nails pass between the roller means. Immediately
before application of the adhesive tapes the adhesive strands 7 are
molten by a heating device 8. After the passage of the row of nails
between the roller means the adhesive strands are cooled to a set
state by a cooling device 9. The strip of nails 4' made in the tape
and adhesive applying station 5 is pulled forward by a feed
assembly 10 along the conveying chute 3 and transferred to a
severing station 11 in which the continously advanced strip of
nails is cut into predetermined lengths which are fed from the
chute 3 into a strip catching and stacking station 12 partly shown
in FIG. 2F on section line 2F--2F in FIG. 8.
The above mentioned work stations are shown more in detail in plan
view in FIGS. 2A-2F. As already mentioned, the vibration feeder 1
is an apparatus of a known type for feeding nails from a randomly
oriented stack to a peripheral chute 2 which as shown in FIG. 2A is
connected to the conveying chute 3 which is formed by two bars 3a.
According to the invention, gravity and the inclination of the
conveying chute 3 (which is adjustable) in relation to the
horizontal plane is exploited to determine the angle of the nail
shanks to an assumed plane extending through the nail heads or nail
points in the row of nails, that is in FIG. 9 the angle .alpha.
between the nail shanks and the tapes 6 applied in the tape and
adhesive applying station and adhered in parallel with the bars 3a.
This simplifies the introduction of the nails in correct position
into the tape and adhesive applying station 5 and permits a simple
setting of the angle between the nail shanks and the longitudinal
direction of the tapes 6 adhered thereto in that the chute 3 has
one of its ends pivotally mounted in the machine frame.
In FIG. 2A there is shown at 15 a magnetic type sensing means which
is mounted on the bars 3a and which magnetically senses the
presence of nails in the chute and is adapted, via electrical leads
16, to sense a feed pulse to the vibration feeder 1 if the sensing
means senses a condition in which no more nails are advanced in the
chute beneath it. A sensing means 17 in the form of a photoelectric
cell assembly is mounted on the rails 3a in a position between the
sensing means 15 and the tape and adhesive applying station 5. This
sensing means 17 is arranged so as to have its photoelectric cell
sense the height position of the nail heads on the bars 3a. If for
some reason a nail head has been caught on the heads of two
adjacent nails this may disturb the operation of the tape and
adhesive applying station. The sensing means upon arrival of such a
wrongly positioned nail delivers an electrical signal and transmits
it via electrical leads 18 to a solenoid valve (not shown) by which
air is admitted to a cylinder 19 for moving a piston 19' between
the nails in the row of nails 4 at the moment when the wrongly
positioned nail arrives in the region of the piston 19'. The piston
19' moves the nails apart and thus causes the wrongly positioned
nail to fall into correct position. The two assemblies 17, 19 thus
automatically correct wrong nail positions during the movement of
the nails towards the tape and adhesive applying station 5. These
two assemblies 17, 19 may naturally be replaced by equivalent means
giving the corresponding result.
The nails are advanced along the conveying chute to the tape and
adhesive applying station 5 by sliding along said chute. Said chute
can be so arranged as to be given vibration pulses by means of a
separate vibration generator or by means of the vibration feeder 1
to facilitate conveyance of the nails.
The tape and adhesive applying station 5 includes as main
constituents two wheels 20, 22 mounted for rotation in the machine
frame 14 (see FIG. 5), and at least one of said wheels 20 has a
configuration similar to a gear wheel in that its periphery is
formed with obliquely cut grooves 21 which have a groove division
corresponding to the distance between the nails 4 to be joined by
means of the tapes 6. The angle between the grooves 21 and the
longitudinal axis of the wheel 20 corresponds to the angle of
inclination of the chute 3. The wheels 20, 22 are adapted, upon
arrival of the nails, to catch the shanks of the nails in turn of
order and to move them into the groove 21 of the rotary wheel 20.
The grooves 21 are so disposed as to extend, when they occupy the
position opposite the nails 4a, at right angles to the bars 3a in
order to keep the nails in correct position during the adhering of
the tapes 6. The order wheel 22 may have a smooth periphery and
serves as a counterwheel for pressing the nails into the grooves 21
of the wheel 20 and for holding the nails in said grooves during
the movements of the nails through the tape and adhesive applying
station. The grooved wheel 20 is adapted to be driven in
synchronism with two pulling rollers 23, 24 in the feed assembly 10
which will be described later on.
In FIG. 3 the grooved nail fixation wheel 20 and the smooth
counterwheel 22 are shown holding a nail 4a which depends from the
chute 3 in vertical position between two tape pressure rollers 25,
26 which like the wheels 20, 22 are mounted in the frame 14 on
either side of the nails 4a.
In FIG. 3 the nails are assumed to move towards the plane of the
paper which is indicated by the arrows for the movement of the
wheels 20, 22 and the pressure rollers 25, 26. The nail fixation
wheels 20, 22 are mounted each on one shaft 27, 28, and coaxially
with each shaft 27, 28 there is carried beneath the respective
wheel 20, 22 a tape guide roll 29 and 30, respectively, over which
a paper tape 6 with glue strands 7 applied to the outer side
thereof is passed to the row of nails (represented in FIG. 3 by a
nail 4a) and the respective pressure roller 25, 26. Each nail 4a
which moves in between the nail fixation wheels 20, 22 and is
grasped by them is held in correct position when the pressure
rollers 25, 26 press the adhesive tapes 6 to the shank of the nail.
The advance of the nails and the tapes 6 through the tape and
adhesive applying station, which is realized by the wheels 20, 22
and the rollers 29, 30, is aided by the feed assembly 10 which
pulls forth the finished strip of nails with the aid of the two
pulling rollers 23, 24 which are driven by an electric motor 31
(only diagrammatically shown in FIG. 1) via a chain transmission 32
which also drives the grooved nail fixation wheel 20 and the
corresponding roller 29 and, if desired, also the smooth nail
fixation wheel 22.
Already before the initiation of the operation the tapes 6 are
extracted from tape rolls 35 (FIG. 2C) in the frame and moved in
between the pulling rollers 23, 24 of the feed assembly 10, whereby
pull power is exerted from the very beginning on the row of nails
over the entire distance from the feed assembly 10 to the tape and
adhesive applying station 5. As the tapes 6 are pulled forth two
parallel strands 7 of adhesive are applied on each tape by means of
a known adhesive applicator 36. As already mentioned the adhesive
is a thermoplastic resin which is fed in molten condition through
two nozzles one for each tape. This device will be more fully
described later on.
The tape and adhesive applying station 5 includes a guide member 38
(FIG. 3) which is mounted in an oblique position in the frame on
the same side of the row of nails as the wheel 20 and serves to
guide the nails in between the fixation wheels 20 and 22 and the
pressure rollers 25, 26 in cooperation with a jet of air blown from
a nozzle 39 disposed on the other side of the row of nails and
connected to a source of air under pressure, directing the air jet
towards the row of nails and the guiding member 38 to move the
shanks of the nails apart so that they will readily fall one into
each groove 21 of the wheel 20. As shown in FIG. 2B, the heating
device generally designated 8 in FIG. 1 comprises two hot air
blowing nozzles 40 disposed on either side of the row of nails 4 at
the inlet side of the pressure rollers 25, 26 by means of which
nozzles the adhesive strands are heated to a suitable condition
immediately before their arrival at the application point. The
cooling device 9 also comprises two blowing nozzles 41 which are
mounted on the outlet side of the pressure rollers 25, 26 to blow
cold air towards the adhered paper tapes whereby setting of the
strands of adhesive is accelerated.
The smooth fixation wheel 22 is carried on the lower end of the
shaft 28 provided therefor, which is movable towards the row of
nails by means illustrated in FIGS. 2B and 5. These means include a
frame 46 which is movable on two parallel guide rods 45 and carries
a bearing housing 26' in which the shaft 28 has its upper end
mounted. The frame 46 is spring-loaded towards the row of nails by
two springs 47 on the rods 45. These springs are interposed between
the frame 46 and a bar 48 which is connected at its ends to two
sleeves 49 slidable on the guide rods 45. The bar 48 is connected
to the frame 46 by means of a screw 50 which freely passes through
the frame 46 against which it bears with a head formed as a hexagon
nut 51, and is screwed into a threaded bore in the bar 48 against
which a stop nut 52 bears. The bar 48 is further connected to a
shaft 53 which is placed beneath the screw 50. The shaft 53 is
movably mounted in a block 54 connected to the frame 14 and carries
in a fork-shaped end portion a guide roller 55 which engages in an
eccentrically arranged slot 56 in a sector-shaped disk 57 which is
rotatably mounted on a shaft 58 and is operable by means of a
handle 59. By rotation of the disk 57 by means of the handle 59 the
shaft 53 can be moved in the one or other sense by engagement of
the guide roller in the slot, and as a result of the frame 46 and
the wheel 22 can rapidly be retracted to a free position with
respect to the row of nails to facilitate access should the paper
tapes rupture or other faults occur. In normal operating position
the wheel 22 is preloaded by the springs 47 on the guide rods 45
towards the grooved wheel 20. The spring load is adjustable by
means of the screw 50 in the manner that will be apparent without
difficulty from the foregoing.
As is shown in FIG. 1 the tape guide rollers 29, 30 mounted on the
shaft 27 of the grooved wheel 20 and on a separate shaft 28' are
vertically adjustable to permit changing the position for the
application of the tapes 6 (omitted in FIG. 5) on the shanks 4a on
the nails. To this end, the shafts 27, 28' in the area above the
columns 60, 61 in which they are mounted, are of a length
considerably greater than the width of the guide rollers 29, 30,
and the guide rollers are movably mounted on the shafts 27, 28. The
shafts and the rollers 29, 30 are formed with keyways 62 and are
coupled by means of coupling keys 64 (see FIG. 4) so that
specifically the wheel 20 can be rapidly exchanged for another
wheel having other grooves 21. To fix the guide rollers in the
height position set each guide roll has a threaded radial bore in
which engages a fixation screw 63 which is countersunk in said bore
so as not to damage the paper tape. The two pressure rollers 25, 26
are mounted on arms 65, 66 which are pivotally mounted in
fastenings 67, 68 on the columns 60, 61 and are pivoted each to a
spring loading device comprising a rod 69 which freely passes
through a bore in a fastening 70 on the respective column 60, 61
and is adjustable by means of a nut device 71 for changing the
tension of a spring 72 which is interposed between the fastening 70
and a spring support at a head 73 on the rod 69.
FIG. 2C shows part of the frame between the tape and adhesive
applying station 5 and the feed assembly 10 which carries the
adhesive applicator 36 and an electric drive motor 80 for operation
of an adhesive feed means. Via a chain transmission 81, an
adjustable gearing 82 and a chain transmission 83 the electric
motor drives the feed means 84 for pulling forth a strand of solid
thermoplastic adhesive from a supply thereof.
The adhesive applicator 36 is of a known type. Therefore, it will
not be necessary to describe this applicator in detail. It should
be mentioned, however, that it includes a heating cabinet 88 and a
device on which is carried a roll of adhesive strand in solid
condition. This strand is pulled off the roll by the drive 80-83
and moved to a channel in the heating cabinet where the strand is
molten by heat from one or more electric elements in the form of
so-called heat cart-ridges 89. The molten resin adhesive is led
through distributing channels 90 to two double nozzles 91 each
delivering two parallel strands 7 (see FIG. 3) of liquid resin
binder to each paper tape 6 at the point where said tape is pulled
off the respective tape roll 35. When the tape is pulled off the
respective roll 35 the tape is turned at 6' and then passes over a
guide roller 92 (FIG. 2B) to a corresponding guide roller 29, 30
beneath the wheel 20 and 22, respectively, so that the strands of
adhesive upon arrival at the tape and adhesive applying station 5
are facing the nail conveying path. Melting of the adhesive can be
controlled automatically by means of a thermostat 93.
The entire adhesive applicator 36 in FIG. 2C is movably suspended
in the frame by means of double acting cylinders 93 for shutting
off the supply of adhesive.
FIGS. 2D and 7 show the feed assembly 10 for pulling forth the
strip of nails 4' made in the tape and adhesive applying station 5.
The feed assembly includes said pulling rollers 23, 24 which bear
against the strip of nails 4' and are driven by the electric motor
31, and adjustable gearing 100 with slipping clutch, and a chain
transmission 101 which may be part of the transmission 32 driving
the grooved nail fixation wheel 20.
The drive shafts 102, 103 for the pulling rollers are rotatably
mounted each in a hollow column 104 on the frame. Each of the two
shafts carries at the lower end projecting from the frame 14 a
sprocket wheel which is part of the chain transmission 101. In the
embodiment illustrated one pulling roller 24 is not mounted
directly on the main drive shaft but instead carried on the lower
end of a vertical shaft 105 which is mounted in a bearing housing
106 supported on a horizontal arm 107. Said arm is pivotally
mounted in a bearing in a bearing housing 108 on the upper end of
the main shaft 102 in the manner clearly apparent from FIGS. 2D and
7 so as to permit being swung towards or away from the row of nails
4'. Moreover, the arm is connected by rod means 109 to a tension
spring 110 which is connected to a lever system 111 by means of
which the spring can be slackened to move the pulling roller aside.
The spring tension is adjustable by means of a threaded bar and an
adjusting nut 112. Driving power from the main shaft to the pulling
roller 24 is transmitted by means of a sprocket wheel 114 on the
main shaft beneath the bearing housing, a short chain 115 and a
sprocket wheel 116 to the shaft 105 carried by the arm 107. As the
arm can be swung about the center of the sprocket wheel and the
main shaft the chain tension is not altered upon position changes
of the arm.
If considered suitable or desirable the other main shaft and the
corresponding pulling roller 23 can be mounted in the same way in
the frame. In the embodiment illustrated it is possible not only to
adjust the pressure of one pulling roller but also to swing said
pulling roller completely away to permit access to the area of the
row of nails. However, the embodiment illustrated has been chosen
to ensure or facilitate centering of the pulling rollers with
respect to the row of nails.
FIG. 2E shows a strip severing means which comprises a knife blade
120 fixedly mounted in the frame 14 on one side of the row of
nails, and a guide 121 fixedly mounted on the other side of the row
of nails and formed in its end with a slot containing a knife blade
120'. The knife blade 120' is movable towards the row of nails by
means of a pneumatic cylinder 122 mounted in a holder in the frame
and connected to a solenoid valve 123 which is electrically
connected to a counter 124 and via this counter to a photoelectric
cell unit 125. The photoelectric cell unit senses the arrival of
the end of the strip of nails (not shown in FIG. 2E) and sends a
pulse to the counter which then receives one pulse for each nail
passing the photoelectric cell. After a given number of pulses
corresponding to the desired number of nails the counter sends a
pulse to the solenoid valve, the cylinder 122 being operated to
sever the strip. Severing takes place with a short delay or by such
a time adaptation of the pulse from the counter that the knife
blade always cuts through the strip between two nails.
By a simple adjustment of the counter the severing means in FIG. 2E
can be set for different lengths of strips of nails and different
sizes of nails.
The strips of nails are passed along the chute 3, as for example
under the influence of the force of gravity from the severing means
in FIG. 2E to the strip catching and stacking station 12 in FIG.
2F. This station includes a strip catching means 130 which is
positioned at a lower level than the conveying chute and comprises
two electromagnets 131 which are adapted to be energized every
second time for catching the strip of nails 4" (FIG. 8) which they
arrive at this station 12 and are allowed to fall from the chute
between the two magnets. The magnets are supported by arms 132
which are connected to a turning mechanism which is driven by two
pairs of double-acting cylinders 133, 134 via a lever system. The
cylinders 133, 134 cooperate with one another and with a fifth
cylinder 136 in the following manner.
The last section of the conveying chute 3' is separated (see FIG.
8) from the remaining part 3 of the chute and consists of two short
bars 3a' each of which is hung on the ends of one link in a linkage
140 which is carried by a frame 141 and is connected to the
cylinder 136 (double-acting) by means of which the linkage is
operable so as to move the rails 3a' apart and together. The
cylinder is controllable via a solenoid valve (not shown) which is
electrically connected to a limit switch 143. When a strip of nails
4" arrives at the limit switch it delivers an opening pulse via the
solenoid valve to the cylinder 136 which via the linkage 140 moves
the bars 3a' apart. The switch 143 is adapted, every second time it
is operated by a strip of nails 4", to energize one magnet 131a and
every second time the other magnet 131b for catching a falling
strip of nails 4' when the bars 3a' are opened. The magnet which is
energized and catches a strip of nails is swung downward in that
one of the two cylinders 133 in FIGS. 2F and 8 is activated and via
the lever arm 135 lowers the magnet support arm 132. This will
actuate one of the cylinders 134 and said cylinder then rotates the
magnet support arm through 90.degree. via a crank arm system shown
at 144, a limit switch 145 being actuated and breaking the circuit
of the operated magnet 131a of 131b. In this way the strips of
nails are deposited in a box placed beneath the turning mechanism
described so that every second strip of nails is placed with the
heads in one direction and every second strip of nails in the
opposite direction, as is indicated in FIG. 8.
For fault detection fault sensing means, for instance of the
photoelectric cell type, may be placed at points spaced along the
conveying track. Such a fault sensing means can be combined with
the severing means to order it to become operative when a defective
nail strip portion is sensed, and in that case the severing means
shall become operative to cut away the defective section. In this
operation the limit switch 142 is disabled and thus allows the
defective nail strip portion to pass for discarding. FIG. 9 shows a
strip of nails 4" made in the machine. The angle .alpha. between
the horizontal plane and the conveying chute 3 determines the angle
.alpha. between a line at right angles to the longitudinal section
of the tapes 6 and the shanks of the nails. By a simple alteration
of the inclination of the nail conveying chute 3 and angle .alpha.
can be altered to fit different nail driving tools. The chute may
be pivotally suspended in the frame 14 at its lower end at a point
150 in FIG. 8, permitting the entire chute including the work
stations 1, 5, 10, 11, 12 to be swung about this point.
Alternatively, the magazine and the chute may be pivoted to the
frame 14 at the upper end for the same purpose. A simple operating
means 115 can be arranged at the magazine for realizing the angular
positioning of the chute. A further possibility is to make part of
the frame 14 swingable in relation to a foundation.
As is apparent from the foregoing, the relatively complicated
operations can be effected by means of a relatively simple machine
the operating cycles of which are controlled and realized in a
simple manner by mechanical transmission elements, electronic
control means and pneumatic operating means. Particularly the
advance of the nails to the tape and adhesive applying station 5
implies an extraordinarily great simplification and the same can be
said of the applying station proper with its fixation wheels, tape
guide rollers and tape pressure rollers. A further essential
advantage is that nails of rectangular section as well as of round
section can be handled in the machine according to the invention
and that an adjustment between different types of nails and sizes
of nails can be effected in a short time and by simple changes.
* * * * *