Note: Descriptions are shown in the official language in which they were submitted.
~8729
BACKGROUND OF TilE INVENTION
-
Caulking guns are well-known in the art and may be
manually or power operated. Usually they are designed to
dispense caulking compound from a pre-packaged cartridge by
driving a piston through the cartridge to expel compound from
a nozzle.
One power driven caulking gun disclosed in the art
utilizes an electric hand drill as the power source. In that
case, the device is secured to the device above and parallel
with the drive shaft and is drivably coupled with the drill
by a flexible cable being clamped at one end within the chuck
o~ the drill and secured at the other end to gearing of the
device.
Motion is transmitted to the gearing on rotation of
the drive shaft through the flexible cable and is translated
into longitudinal motion of a piston to dispense caulking
compound from a nozzle through speed reduction gearing and a
sophisticated drive train.
SUMMARY OF T~E INVENTION
I-t is an object of the invention to provide a very
simple reliable caulking gun possibly using an electric drill
as a power source.
It is another object of the invention to provide a
caulking gun which may be manufactured by modifying the
production of electric drills.
It is an alternate object of the invention to
provide a caulking gun accessory for an electric drill.
Accordingly, the invention provides a caulking hand
gun comprising a power source located in a housing and having
a variable speed reversible direction drive shaft, and
control means to control -the speed of the drive shaft; and
caulking means comprising a cylinder for receiving
caulking compound abutting said housing at one end and
~187'~9
securable thereagainst, said cylinder having a dispensing
nozzle at the other end, a pis-ton within said cylinder having
a telescopically extensible piston rod of at least three
sections, one end section of which being secured to said
drive shaft and the other end section being attached to said
piston, the sections being in screw threaded engagement one
with another to be successively telescopically extensible on
operation of said drive,
whereby on extension of said piston rod by means of
operation of said drive, said piston acts to dispense
caulking compound from said nozzle.
IN THE DRAWINGS
Figure 1 illustrates a side view of one embodiment
of the invention with the side wall of the cylinder cut away
to show the interior.
Figure 2 is a section on the line A-A of Figure 1
with the side wall of the cylinder complete.
Figure 3 is a view similar to that of Figure 1 but
showing an alternate embodiment.
Figure 4 is a side view of one telescopic piston
rod showing screw threaded connections between sections.
In the drawings, an elPctric power source in a
housing 1 fed by a cable 2 is provided with drive shaft 3
having variable speed and reversible direction controlled
~5 through control switch 4. The arrangement of the power
source in housing 1, drive shaft 3, and control switch 4 may
conveniently be that of a conventional electric hand drill,
either adapted in manufacture for the addition of a caul.king
cylinder 22 or provided with means to attach caulking
7:;~9
cylinder 22 as an accessory for the electric drill. The
caulking cylinder 22 is secured to the housing 1 by any
convenient means and may, when the caulking cylinder is an
accessory, be releasable from the housing 1 leaving the
assembly of the power source in the housing 1, with cable 2,
drive shaft 3 and control switch 4 operable independently as
an electric drill. The caulking cylinder 22 may be such as
to accept caulking compound from a bulk source (see Figure 1)
or to accept a pre-packaged cartridge 5 of caulking compound
(see Figure 3).
When the cylinder 22 is to accept bulk caulking
compound any conventional access means (not shown) may be
provided for filling and re-filling the cylinder. If the
cylinder wall is continuous and the cylinder is sealed, caulk
can be introduced thereinto by suctioll through the nozzle.
The cylinder 22 is provided with a nozzle 6 to
dispense caulking compound. The nozzle 6 is located on a cap
7 which may be removable from cylinder 22 so that different
types of nozzle 6 can be interchanged into the device.
Inside cylinder 22 is piston 8 located at one end
of telescopic piston rod 9, the other end of which is secured
to the drive shaft 3.
As shown in Figure 1, the drive shaft 3 is directly
connected to piston rod section 10 but such connection,
especially when the caulking arrangement is an accessory for
an electric hand drill, may be through a drill chuck 11
(Figure 3).
The piston rod 9 comprises hollow section 10 fixed
at one end to drive shaft 3 to rotate wlth it and extending
,r
729
axially within cylinder 22. Section 10 is provided with
internal screw threading 12 at its other end, the screw
threads 12 engaging with screw threads 13 extending over the
length of an intermediate section 14 of piston rod 9.
Section 14 is a hollow section oE smaller radius
than section 10 so that it can nest within it. Rotation of
the sections 10, 14 relative to each other causes, through
the screw threads 12, 13 retraction of section 14 into, or
extension of section 14 from, section 10. Section 14 is
provided with a stop 15 to prevent removal from section 10.
Similarly to section 10, section 14 has internal
screw threading 16 at its end distant from drive shaft 3.
The screw threading 16 engages with screw threading 17
extending over the length of section 18 of piston rod 9.
Section 18 is a rod carrying piston 8 at one end and having a
stop 19 at the other end to prevent complete removal from
section 14. Relative rotation between sections 14 and 19
causes retraction or extension of section 19 from section
14.
At least when a source of bulk caulking compound is
to be used, piston 8 is provided with means to prevent its
rotation in cylinder 22. When cylinder 22 is for bulk
caulking compound (see Figures 1 and 2) the means to prevent
rotation may be a guide tip 20 running longitudinally
internally on cylinder 22 cooperating with a slot 21 in the
: periphery of piston 8. Alternatively, a lug on the piston
periphery may run in a groove of the cylinder 22.
Caulking compound from a bulk supply can be
introduced into the cylinder 22 by suction through the nozzle
6 by operation of the piston 8 in the reverse manner to that
for the extrusion of caulking compound.
When the cylinder is for a cartridge of packed
caulking compound, it may be that friction between the
1:118729
cartridge and the piston is sufficient to prevent the piston
turning. However, it may be advantageous to provide the
piston with a lug whereby it will forge a groove in the
cartridge material and act as an added restraint against the
piston turning.
To make the device ready to operate, the sections
14 and 18 are retracted fully :into their nesting positions.
The cylinder 22 is filled with caulking compound or provided
with a caulking cartridge. The device is then ready to
operate.
, To operate the device, the drive shaft is rotated
forwardly at the desired speed by operation of control switch
4. Section 10 of piston rod 9 rotates with drive shaft 3
and, since there are no restraints on section 14 at this
time, section 14 tends to rotate with it. Section 18 is
restrained from rotation by the restraining means acting on
piston 8 and hence there is relative rotation between section
18 and section 14. Due to the unscrewing action between
screw threads 16 and 17 section 18 starts moving
~0 longitudinally out of section 14. Piston 8 acts on caulking
compound to dispense it through nozzle 6. When stop 19
abuts screw threads 16 no further unscrewing is possible
between sections 18 and 14 so section 14 becomes locked with
section 18 against rotation. At this point relative rotation
; 25 between sections 10 and 14 begins and section 14 starts
moving longitudinally out of section 10 thus further
actuating piston 8. Finally, stop 15 abuts screw threads 12
and no further extension is possible. A suitable total
extension is 8 inches. To prevent damage to the power source
at this point it is convenient to provide a warning signal
just before the final stop point is reached. Alternatively,
an automatic clutch can be provided. At, or just before the
~`
729
final stop point, tlle clirecti !l of the drive shaft shoulcl be
reversed to re-nest the sec~ s 10, 14 and 18 so the
cylinder may be resuppliecl with caulking compound.
The telescopic arran~ement of piston rod 9 has
various advantages in that the total length of the device is
controlable. ~ore than three sections can be used if
desired. Moreover, if an ordinary hand drill is used the
control button may be adapted to have a longer than normal
travel so that the speed is more easily controllable.
Although the device has been described for use with
caulking compound it may be used for other materials, e.g.
grease.
