Information
-
Patent Grant
-
6598775
-
Patent Number
6,598,775
-
Date Filed
Friday, August 30, 200221 years ago
-
Date Issued
Tuesday, July 29, 200320 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 227 113
- 227 15
- 227 18
- 227 130
- 227 119
- 227 142
- 227 147
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International Classifications
-
Abstract
A hammer head assembly used in a power hammer for driving a nail into objects to be fastened is constructed to include a nail holder axially slidably mounted in a hollow mounting base and forced out of the bottom side of the mounting base by a spring member, a magnet fixedly provided inside the nail holder and adapted to attract a nail in vertical for driving into the workpiece, and a hammering rod axially inserted into the nail holder and controlled to drive a nail out of the nail holder into the workpiece.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power hammer adapted for to drive nails into objects to be fastened together and, more specifically, to a hammer head assembly for power hammer.
2. Description of the Related Art
FIG. 11
shows a hammer head assembly for power hammer according to the prior art. According to this design, the hammer head assembly comprises a hollow mounting base
8
, the mounting base
8
having an outer thread
81
threaded into the corresponding mounting hole of the power hammer and an axially extended stepped center through hole
82
, a nail holder
7
axially slidably mounted in the axially extended stepped center through hole
82
of the mounting base
8
, the nail holder
7
having a bottom hole
71
adapted to receive a nail
9
having a head
91
, a compression spring
811
mounted inside the mounting base
8
and imparting a downward pressure to the nail holder
7
, a magnet
72
provided inside the nail holder
7
and adapted to attract the nail
9
loaded in the bottom hole
71
of the nail holder
7
, and a hammering rod
73
inserted into the nail holder
7
and adapted to drive the loaded nail
9
into the workpiece. This design of hammer head assembly is practical for driving regular nails into the workpiece, however it is not suitable for driving washer faced screw nails.
SUMMARY OF THE INVENTION
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a hammer head assembly for power hammer, which is suitable for driving any of a variety of nails. It is another object of the present invention to provide a hammer head assembly for power hammer, which positively holds the loaded nail in position for driving. To achieve these and other objects of the present invention, the hammer head assembly comprises an externally threaded mounting base fastened to a mounting hole of the power hammer, the mounting base having an axially extended center through hole extended through top and bottom sides thereof; a nail holder axially slidably inserted into the axially extended center through hole of the mounting base from the bottom side of the mounting base, the nail holder having a longitudinal sliding groove in the periphery thereof, an axially extended center through hole, and a bottom skirt extended around a bottom end of the axially extended center through hole of the nail holder, the bottom skirt having a vertical peripheral wall defining a receiving open chamber adapted to hold the washer of a washer faced screw nail; a spring member provided inside the mounting base and adapted to force the nail holder downwardly out of the mounting base; a hammering rod inserted into the axially extended center through hole of the mounting base and the axially extended center through hole of the nail holder and adapted to drive a nail into the workpiece; and at least one magnet mounted inside the nail holder and adapted to attract a nail for enabling the attracted nail to be driven into the workpiece by the hammering rod.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is an exploded view of a hammer head assembly according to the present invention.
FIG. 2
is an applied view in section of the present invention, showing the hammer head assembly installed in a power hammer.
FIG. 3
is similar to
FIG. 2
but showing the nail driven into the workpiece.
FIG. 4
is a perspective view of an alternate form of the nail holder, showing a plurality of magnetic elements equiangularly spaced from the axially extended center through hole of the nail holder at a distance.
FIG. 5
is a sectional view of a part of the alternate form of the present invention.
FIG. 6
is a perspective view of a washer faced screw nail with a rectangular washer according to the present invention.
FIG. 7
is a perspective view of a washer faced screw nail with a circular washer according to the present invention.
FIG. 8
is a sectional view showing a washer faced screw nail with a plastic washer loaded in the nail holder according to the present invention.
FIG. 9
is an exploded view of an alternate form of the hammer head assembly according to the present invention.
FIG. 10
is a sectional view showing an application example of the hammer head assembly shown in FIG.
9
.
FIG. 11
is a sectional view of the prior art design.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS.
1
˜
3
, a hammer head assembly is shown used in a power hammer
3
, and adapted to drive a washer faced screw nail
4
into a sheet member
45
and a beam (or column)
46
to fix the sheet member
45
to the beam (or column)
46
. The hammer head assembly is comprised of an externally threaded mounting base
1
, a nail holder
13
, a compression spring
111
, and a hammering rod
32
. The mounting base
1
has an axially extended center through hole
11
. The nail holder
13
is inserted into the axially extended center through hole
11
of the mounting base
1
, having a longitudinal sliding groove
135
in the periphery, an axially extended center through hole
134
, and a bottom skirt
131
extended around the periphery of the bottom end. The bottom skirt
131
has a vertical peripheral wall
132
defining a receiving open chamber
133
adapted to hold the washer
41
of a washer faced screw nail
4
. A screw
12
is threaded into a radial screw hole
110
and perpendicularly engaging the longitudinal sliding groove
135
of the nail holder
13
to guide vertical movement of the nail holder
13
in the axially extended center through hole
11
of the mounting base
1
and to stop the nail holder
13
from rotary motion. The compression spring
111
is provided inside the mounting base
1
within the axially extended center through hole
11
and stopped between an upper part of the nail holder
13
and an upper part of the mounting base
1
to push the nail holder
13
downwards relative to the mounting base
1
. The hammering rod
32
is inserted through the axially extended center through hole
134
of the nail holder
13
, having a stepped tip
321
. The top end of the hammering rod
32
is connected to the piston
31
of the power hammer
3
. When the power hammer
3
started, the hammering rod
32
is forced by the piston
31
to drive the washer faced screw nail
4
into the sheet member
45
and the beam (or column)
46
. The washer faced screw nail
4
comprises a screw nail
42
having a head
421
, a washer
41
fastened to the screw nail
42
and closely attached to the head
421
of the screw nail
42
at a bottom side. The washer
41
has chamfer angle
411
in each of the four corners. The receiving open chamber
133
of the nail holder
13
fits the contour of the washer
41
. Further, an annular magnet
136
is provided inside the receiving open chamber
133
of the nail holder
13
around the bottom end of the axially extended center through hole
134
and adapted to attract the head
421
of the washer faced screw nail
4
, for enabling the washer faced screw nail
4
to be positively and accurately driven into the sheet member
45
and the beam (or column)
46
by the hammering rod
32
upon reciprocating action of the piston
31
of the power hammer
3
.
Referring to
FIGS. 4 and 5
, multiple magnetic elements
137
may be provided inside the bottom skirt
131
and equiangularly spaced around the axially extended center through hole
134
at a distance to attract the washer
41
of the washer faced screw nail
4
.
The skirt
131
of the nail holder
13
may be made in any of a variety of shapes to fit different washer faced screw nails. The washer faced screw nail shown in
FIG. 6
has a rectangular washer
41
fastened to the screw nail
42
at the bottom side of the head
421
of the screw nail
42
. The washer faced screw nail shown in
FIG. 7
has a circular washer
43
fastened to the screw nail
42
at the bottom side of the head
421
of the screw nail
42
.
FIG,
8
shows an alternate form of the present invention adapted to drive a washer faced screw nail with a plastic washer into the workpiece. As illustrated, the nail holder
13
has a positioning ring
138
provided inside the receiving open chamber
133
at the bottom end of the axially extended center through hole
134
. The positioning ring
138
is made of non-magnetic metal. When the plastic washer
44
of the washer faced screw nail loaded in the receiving open chamber
133
, the head
421
of the screw nail
42
is inserted into the positioning ring
138
and attracted by the magnet
136
in the axially extended center through hole
134
around the tip
321
of the hammering rod
32
.
FIGS. 9 and 10
show another alternate form of the present invention practical for driving a screw nail with a plastic washer
44
as well as a regular nail
2
According to this embodiment, the hammer head assembly is comprised of an externally threaded mounting base
5
having an axially extended center through hole
51
, a top-flanged nail holder
6
axially movably mounted in the axially extended center through hole
51
of the mounting base
5
and partially extended out of the bottom side of the mounting base
5
, a compression spring
511
mounted within the mounting base
5
and imparting a downward pressure to the nail holder
6
, and a hammering rod
32
inserted into the axially extended center through hole
61
of the nail holder
6
and controlled to drive the nail into the workpiece. The hammering rod
42
has a stepped tip
321
. The nail holder
6
has a positioning ring
63
made of non-magnetic metal and fixedly provided within the bottom end of the axially extended center through hole
61
, and an annular magnet
62
fixedly provided inside the axially extended center through hole
61
above the positioning ring
63
. The inner diameter of the positioning ring
63
is greater than the inner diameter of the magnet
62
. When the head
421
of the screw nail
42
(or the nail
2
) inserted into the positioning ring
63
, the magnet
62
attracts the screw nail
42
(or the nail
2
), enabling the screw nail
42
(or the nail
2
) to be accurately driven into the workpiece.
A prototype of hammer head assembly for power hammer has been constructed with the features of FIGS.
1
˜
10
. The hammer head assembly for power hammer functions smoothly to provide all of the features discussed earlier.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
Claims
- 1. A hammer head assembly used in a power hammer for driving a nail into objects to be fastened, comprising:an externally threaded mounting base fastened to a mounting hole of said power hammer, said mounting base having an axially extended center through hole extended through top and bottom sides thereof; a nail holder axially slidably inserted into the axially extended center through hole of said mounting base from the bottom side of said mounting base, said nail holder having a longitudinal sliding groove in the periphery thereof, an axially extended center through hole, and a bottom skirt extended around a bottom end of the axially extended center through hole of said nail holder, said bottom skirt having a vertical peripheral wall defining a receiving open chamber adapted to hold the washer of a washer faced screw nail; a spring member provided inside said mounting base and adapted to force said nail holder downwardly out of said mounting base; a hammering rod inserted into the axially extended center through hole of said mounting base and the axially extended center through hole of said nail holder and adapted to drive a nail into the workpiece; and at least one magnet mounted inside said nail holder and adapted to attract a nail for enabling the attracted nail to be driven into the workpiece by said hammering rod.
- 2. The hammer head assembly as claimed in claim 1, wherein said at least one magnet includes a plurality of magnetic elements fixedly mounted inside said bottom skirt and equiangularly spaced from the axially extended center through hole of said nail holder at a distance.
- 3. The hammer head assembly as claimed in claim 1, wherein said at least one magnet includes an annular magnet provided inside said receiving open chamber of said nail holder around one end of the axially extended center through hole of said nail holder.
- 4. The hammer head assembly as claimed in claim 1, wherein said nail holder has a longitudinal sliding groove in the periphery thereof; said mounting base comprises a radial screw hole, and a screw threaded into said radial screw hole and perpendicularly engaging the longitudinal sliding groove of said nail holder to guide axial movement of said nail holder in the axially extended center through hole of said mounting base and to stop said nail holder from rotary motion.
- 5. A hammer head assembly used in a power hammer for driving a nail into objects to be fastened, comprising:an externally threaded mounting base fastened to a mounting hole of said power hammer, said mounting base having an axially extended center through hole extended through top and bottom sides thereof; a top-flanged nail holder axially slidably inserted into the axially extended center through hole of said mounting base from the top side of said mounting base, said nail holder having an axially extended center through hole; a spring member provided inside said mounting base and adapted to force said nail holder downwardly out of said mounting base; a hammering rod inserted into the axially extended center through hole of said mounting base and the axially extended center through hole of said nail holder and adapted to drive a nail into the workpiece; a non-magnetic annular metal positioning ring fixedly mounted within the axially extended center through hole of said nail holder in flush with the bottom side of said nail holder; and an annular magnet fixedly provided within the axially extended center through hole of said nail holder at a top side of said non-magnetic annular metal and adapted to attract a nail in said non-magnetic annular positioning ring for enabling the attracted nail to be driven into the workpiece by said hammering rod.
US Referenced Citations (6)