Engraving head

An engraving head that includes a movement mechanism for moving an engraving stylus within the body housing of the engraving apparatus is provided. The movement of the engraving stylus causes the tip of the engraving stylus to approach and recede from an engraving surface. The movement mechanism contains a movable body and a first energizing means. The movable body moves in association with a movement space member's inner circumference. The movement space member is positioned inside the body housing. The first energizing means is employed to energize the movable body in a direction away from the engraving surface. Additionally, a second energizing means serves to energize the movable body in a direction towards the engraving surface against the opposing energizing force of the first energizing means. The second energizing means may be, for example, compressed gas. As the movable body travels downward towards the engraving surface, the tip portion of the engraving stylus also approaches the engraving surface. When the energizing force of the second energizing means is released or is less than a predetermined value, the movable body and the tip portion of the engraving stylus recede from the engraving surface.

FIELD OF THE INVENTION 
The invention relates to the field of engraving instruments, and more 
particularly to an engraving head used in conjunction with an engraving 
apparatus to engrave, for example, letters, symbols or figures on the 
surface of an engraving work piece. 
BACKGROUND OF THE INVENTION 
The preexisting technology will be discussed in reference to FIG. 3. As 
shown in FIG. 3, an engraving head 50 comprises a body housing that 
includes an end portion 52 and a top portion 53 that are joined together. 
Cap 51 attaches to the upper portion of end portion 52. The body housing 
54 mounts to an engraving apparatus (which is not shown) and moves in X 
and Y directions by a movement means attached to the engraving apparatus 
(which is not shown). In addition the prior art contains an up-and-down 
movement means (which is not shown) that moves body housing 54 upward and 
downward. The up-and-down movement means may be an air cylinder, a sliding 
mechanism or the like. The up-and-down movement means couples to the 
engraving head 50. 
The body housing 54 includes a vibration generating mechanism used in 
conjunction with compressed gas to cause engraving stylus 60 to vibrate 
slightly up and down. The vibration generation mechanism will be discussed 
below. A compressed gas supply port 51a is provided on cap 51. The 
compressed gas supply port 51a continuously supplies the compressed gas to 
inner room 55 of the end portion 52. The compressed gas enters inner room 
55 and flows downward through penetrating holes 55a and encounters O-ring 
56. The introduction of the compressed gas increases the gas pressure 
within inner room 55. (As the volume of the compressed gas increases 
within inner room 55, the pressure of the gas increases.) 
When the gas pressure applied to O-ring 56 is less than a predetermined 
value, O-ring 56 is energized upward. The coils of helical compression 
spring 57 extend upward generating an upward movement of flanged portion 
60a and O-ring 56. O-ring 56 is energized upward to cover penetrating 
holes 55a, which are formed at the lower end of end portion 52. As the gas 
flows into inner room 55, the pressure increases and energizes O-ring 56 
downward. 
When the gas pressure applied to O-ring 56 exceeds a predetermined value, 
engraving stylus 60, O-ring 56 and flanged portion 60a are energized 
downward against the energizing force of helical compression spring 57. 
This downward motion of O-ring 56 creates small spaces between O-ring 56 
and O-ring containing groove 52a. These small spaces permit the compressed 
to pass into the engraving stylus operating room 53a of top portion 53. 
After entering engraving stylus operating room 53a, the compressed gas 
flows through a pair of discharge holes 53b and exits top portion 52. 
As the compressed gas exits, the pressure decreases within engraving head 
50, and the gas pressure applied to O-ring 56 falls below the 
predetermined value. Once again, O-ring 56 and engraving stylus 60 are 
energized upward. Due to the decreased pressure, helical compression 
spring 57 expands upward generating an upward movement of flanged portion 
and O-ring 56. O-ring 56 is energized upward to cover penetrating holes 
55a. As previously discussed, the gas pressure inside inner room 55 
increases again. 
The introduction of the compressed gas generates the intermittent expansion 
and contraction motion of the helical compression spring, which in turn 
causes O-ring 56 and engraving stylus 60 to slightly vibrate up and down. 
During the vibration of engraving stylus 60, the up-and-down movement means 
(which is not shown) guides and lowers the entire engraving head 50 to 
press the tip of engraving stylus 60 against an engraving surface T'. The 
up-and-down movement means may be an air cylinder, a sliding mechanism or 
the like. Then, the engraving head 50 is moved in the X and Y directions 
by the movement means to engrave letters, symbols, figures or the like on 
the engraving surface T'. 
In order to produce engravings that are not expressed with a single brush 
stroke on an engraving surface, the engraving apparatus of the prior art 
must stop engraving, the up-and-down movement means lifts the entire 
engraving head 50 and the movement means repositions according to the 
desired X and Y coordinates. Next, engraving head 50 is moved downward at 
a predetermined position and the engraving procedure is resumed. 
In order to press the tip of engraving stylus 60 against engraving surface 
T' during engraving and to perform engravings that are not expressed with 
a single brush stroke on the engraving surface, the prior art requires 
that the engraving apparatus includes an up-and-down movement means. The 
addition of the up-and-down movement means increases the cost and the size 
of the engraving apparatus. Furthermore, the repetitive operations needed 
to perform engravings that are not expressed with a single brush stroke on 
the engraving surface is time consuming. As discussed above, the prior art 
requires that the engraving apparatus pauses the engraving process so that 
the up-and down movement means may move the whole engraving head 50 
upward. Then, engraving stylus 60 is moved in the X and Y directions to a 
predetermined position. Thereafter, the engraving head 50 is once again 
lowered to engraving surface T'. This repetitive process is time 
consuming. 
SUMMARY OF THE INVENTION 
A general object of this invention is to overcome these and other drawbacks 
of prior art engraving devices. 
An object of the invention is to provide an engraving head that produces 
engraving which are not expressed with a single brush stroke on a 
engraving surface. Another object of the invention is to provide an 
engraving head that does not require an up-and-down movement means, such 
as a sliding mechanism or an air cylinder. 
According to one embodiment of the invention, the engraving head comprises: 
a means for moving the engraving head in a plane that is parallel to an 
engraving surface of a work piece to be engraved; an engraving stylus 
partially disposed within a body housing, the engraving stylus is capable 
of slightly vibrating and striking its tip portion against the engraving 
surface to form a recess in the engraving surface; and a movement 
mechanism for moving the engraving stylus within the body housing as the 
tip portion of the engraving stylus is extended to and withdrawn from the 
engraving surface. The engraving stylus of the present invention can be 
positioned within the body housing at a predetermined position. 
Thereafter, the engraving stylus can begin to slightly vibrate. 
Accordingly, the engraving head is moved to the desired engraving position 
by a movement means that moves the engraving head in a plane that is 
parallel to the engraving surface of the work piece to be engraved. Then, 
the engraving stylus is moved within the body housing of the engraving 
head by the movement mechanism, so that the tip of the engraving stylus 
approaches the engraving surface. During the slight vibrations of the 
engraving stylus, the tip portion thereof strikes against the engraving 
surface to form a recess or a cavity therein. Simultaneously, the 
engraving head is moved in the plane which is parallel to the engraving 
surface to produce engravings, such as letters, symbols, figures or the 
like in the engraving surface. 
In order to perform engravings that are not expressed with a continuous 
recess, in order words, engravings which are not expressed with a single 
brush stroke on the engraving surface, the following procedure is 
followed. Once the engraving stylus is moved within the body housing by 
the movement mechanism so that the tip portion of the engraving stylus 
recedes from the engraving surface, the movement means positions the 
engraving head to a desired position. Then, the movement mechanism 
positions the tip portion of the engraving stylus near the engraving 
surface. As the engraving stylus vibrates, the movement means moves the 
engraving head in a plane that is parallel to the engraving surface, thus, 
producing engravings. 
In summary, the present invention does not require the addition of an 
up-and-down movement means that lifts the entire engraving head during the 
engraving process since the engraving stylus moves within and relative to 
the engraving head so that the tip portion of the engraving stylus 
approaches and recedes from the engraving surface. Accordingly, for 
example, it is not required for the engraving apparatus to be provided 
with an up-and-down movement means, such as a sliding mechanism or air 
cylinder, that guides the up-and-down movement of the entire engraving 
head. Thus, the present invention discloses a cheaper and a more compact 
engraving device. 
The present invention provides an engraving head that includes a movement 
mechanism for moving an engraving stylus within the body housing of the 
engraving apparatus. The movement of the engraving stylus causes the tip 
of the engraving stylus to approach and recede from an engraving surface. 
The movement mechanism contains a movable body and a first energizing 
means. The movable body moves in association with a movement space 
member's inner circumference. The movement space member is positioned 
inside the body housing. The first energizing means is employed to 
energize the movable body in a direction away from the engraving surface. 
Additionally, a second energizing means serves to energize the movable 
body downward towards the engraving surface against the opposing 
energizing force of the first energizing means. The second energizing 
means may be, for example, compressed gas. As the movable body travels 
downward towards the engraving surface, the tip portion of the engraving 
stylus also approaches the engraving surface. When the energizing force of 
the second energizing means is released or is less than a predetermined 
value, the movable body and the tip portion of the engraving stylus recede 
from the engraving surface. Therefore, the engraving stylus can be easily 
and quickly maneuvered within the body housing by the movement mechanism, 
as the tip portion approaches and recedes from the engraving surface. 
Furthermore, the energizing force of the first and the second energizing 
means may be adjusted so that the movement of the engraving stylus may be 
rapidly performed. Likewise, if compressed gas is used as the second 
energizing means, the gas pressure and the flow rate of the gas may be 
adjusted as needed to energize the movable body to and from the engraving 
surface. This feature also enhances the rapid movement of the tip portion 
towards the engraving surface as the movable body moves downward. 
A pair of penetrating holes are provided within the movable body. The 
penetrating holes may permit the compressed gas to pass through the 
movable body and enter the top portion of the body housing when the second 
energizing means is activated. A flanged portion couples to one end of the 
engraving stylus. At least one or more elastic members serves to cover the 
exit of the penetrating holes. The elastic member is disposed between the 
flanged portion and the movable body in a position that prevents the 
elastic member from shifting to the movable body. As the compressed gas 
intermittently passes between the exit of the penetrating holes and the 
elastic member, slight vibrations are generated. 
According to the invention, the power of the compressed gas can be utilized 
to simultaneously move the tip portion of the engraving stylus towards the 
engraving surface and to generate the slight vibrations of the engraving 
stylus. Further, the elastic member can be positioned and disposed in a 
groove portion formed in the movable body so that the elastic member is 
prevented from shifting to the movable body. 
In accordance with another embodiment of the present invention, the 
engraving head may comprise a body housing, an engraving stylus and a 
movement mechanism. The body housing mounts to an engraving apparatus 
having means for moving the engraving head in a plane that is 
perpendicular to the engraving head. The body housing contains the 
engraving stylus, which vibrates with a small amplitude. The movement 
mechanism moves the engraving stylus within the body housing to extend and 
contract the tip portion of the engraving stylus. With the engraving head, 
the engraving stylus can be moved relative to the body housing. The 
engraving stylus can be extended from the body housing by the movement 
mechanism, and the engraving stylus can be positioned within the body 
housing at a predetermined position, which is determined by a lower 
limiting surface. Thereafter, the engraving stylus can vibrate with a 
small amplitude causing the tip portion thereof to strike against the 
surface of an engraving work piece. After the engraving stylus stops 
vibrating, the engraving stylus can be contracted within the body housing 
by the movement mechanism. Then, the engraving stylus can be positioned 
within the body housing at another predetermined position, which is 
determined by an upper limiting surface. Then, the movement means may 
relocate the engraving stylus to another engraving position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
One embodiment of the invention relates to an engraving head 1 as shown in 
FIG. 1. In FIG. 1, engraving head 1 is provided with a body housing 2. 
Body housing 2 is principally comprised of four major elements, namely, 
end portion housing 3, top portion 4, an engraving stylus 7, and a 
movement mechanism. Top portion 4 connects to end portion housing 3. The 
movement mechanism includes a movable body 5 and a helical compression 
spring 8. 
The body housing 2 mounts to an engraving apparatus (which is not shown) 
and moves in the X and Y directions by a movement means (which is not 
shown). The movement means attaches to the engraving apparatus. The body 
housing 2 may be moved by the movement means if, for example, in a plane 
that is perpendicular to the body housing 2 or in a plane that is parallel 
to an engraving surface T of a workpiece to be engraved. 
The end portion housing 3 contains a compressed gas supply port 3a, an 
inner room 3b and a cylindrical movement space 3c, which connects to inner 
room 3b. The compressed gas introduced by the compressed gas supply port 
3a functions as a second energizing means as it flows from the compressed 
gas supply port 3a and into inner room 3b. 
A cylindrical movable body 5 is slidably disposed inside movement space 3c. 
The configuration of cylindrical movable bodies has a perimeter that is 
approximately the length and shaped of the inner circumference of the 
movement space 3c. The cylindrical movable body may be moved upward or 
downward within the inside movement space 3c. In this embodiment, the 
upward motion of the movable body 5 is limited by an upper surface 3d of 
the movement space 3c. The downward motion of movable body 5 is limited by 
an upper end surface 4c of top portion housing 4. 
Integrally formed within the lower portion of the movable body 5 is an 
O-ring disposing grooved 5a wherein an O-ring 6 is positioned and 
disposed. O-ring 6 may be an elastic member made of rubber or other 
elastic material. The sizing of O-ring 6 allows it to fit snugly within 
movable body 5 so that O-ring 6 does not shift against movable body 5. 
A pair of penetrating holes 5b are provided on movable body 5. Penetrating 
holes 5b extends from the inner room 3b to the O-ring disposing groove 5a. 
O-ring 6 covers the lower end portion of penetrating holes 5b. 
The engraving stylus 7 includes an axis portion 7a, a disc-shaped flanged 
portion 7b and a tip portion 7c. Disc-shaped flanged portion 7b is formed 
on an upper end portion of the axis portion 7a. The tip portion 7c is 
formed on a lower end portion of the axis portion 7a and contains a 
pointed-shaped top end. 
The axis portion 7a of the engraving stylus 7 is inserted into an insertion 
hole 4a and moves slidably upward and downward within axis portion 
insertion hole 4a. 
Helical compression spring 8, which is disposed around axis portion 7a, 
functions as the first energizing means. An upper end portion of the 
helical compression spring 8 directly contacts with the lower surface of 
the flanged portion 7b of the engraving stylus 7. The lower end portion of 
the helical compression spring 8 rests upon a lower surface of an 
engraving stylus operating room 4b, which is formed inside of top portion 
housing 4. 
According to the present embodiment, the movable body is energized upward 
by the expansion of helical compression spring 8 which in turns moves the 
flanged portion 7b of the engraving stylus 7 and O-ring 6 upward. In the 
embodiment shown in FIG. 1, the movable body 5 is in a stationary state. A 
peripheral portion of an upper end surface of the movable body 5 is in 
contact with the upper surface 3d of the movement space 3c. Further, 
O-ring 6 is pressed against penetrating holes 5. Therefore, the lower end 
portion of the inner room 3b is hermetically sealed by the movable body 5 
and O-ring 6. 
Referring to FIG. 2, the engraving operations of engraving head 1 according 
to the present invention will be explained. Initially, the supply of 
compressed gas from the compressed gas supply port 3a is introduced, as 
indicated by an arrow in FIG. 2, into inner room 3b. As the gas pressure 
of inner room 3b increases, the movable body 5 moves downward along the 
inner circumference of the movement space 3c against the energizing force 
of the helical compression spring 8. The movement of the movable body and 
O-ring 6 causes engraving stylus 7 to move downward and to approach 
engraving surface T. 
As shown in FIG. 2, when the lower end surface of the movable body 5 
encounters the upper end surface 4c of the top portion housing 4, the 
downward movements of the movable body 5, O-ring 6 and the engraving 
stylus 7 stop. The tip portion 7c rests at a position near the engraving 
surface T of the work piece. 
In this state, the compressed gas is continuously supplied from the 
compressed gas supply port 3a, so that the gas pressure within inner room 
3b continues to increase. When the gas pressure inside inner room 3b, that 
is, the gas pressure applied to O-ring 6 exceeds a predetermined value, 
the engraving stylus and O-ring 6 moves slightly downward by the pressure 
of the gas exerted against the energizing force of helical compression 
spring 8. Small spaces between the O-ring 6 and O-ring disposing groove 5a 
are generate due to the downward motion. These small spaces allow the 
compressed gas to flow into the engraving stylus operating room 4b. 
Further, the gas discharges from the engraving stylus operating room 4b 
through of a pair of discharge holes 4d formed in top portion housing 4. 
The gas pressure inside inner room 3b, which is under a high pressure until 
the compressed gas begins to exits top portion housing 4, decreases. Thus, 
once again, O-ring 6 is energized upward by the expansion of helical 
compression spring 8 which moves flanged portion 7b slightly upwards. 
Thus, O-ring 6 and engraving stylus 7 are moved slightly upward. 
Accordingly, O-ring 6 is pressed upward to once again cover penetrating 
holes 5b. 
As previously discussed, the gas pressure inside inner room 3b increases 
again. The introduction of the compressed gas generates the intermittent 
expansion and contraction motion of the helical compression spring, which 
in turn generates the small up and down movements of O-ring 6 and 
engraving stylus 7. These small up and down movements are quickly 
repeated. Thus, it becomes the slight up-and-down vibration of the 
engraving stylus 7. The slight vibration may have a small amplitude and a 
large number of vibration frequency. The supply speed of the compressed 
gas or other conditions are established so that the operation time from 
the start of the supply of the compressed gas to the start of the 
vibration of the engraving stylus 7 will be performed within an extremely 
short time frame. 
When the lower end surface of the movable body 5 initially contacts upper 
end surface 4c, tip portion 7c of the engraving stylus 7 is positioned 
nearby engraving surface T of the work piece to be engraved. Then, the 
engraving stylus 7 moves slightly up and down, as described above, causing 
tip portion 7c to repeatedly strike the engraving surface T, so that 
recesses or cavities are formed in the engraving surface T. 
While the engraving stylus vibrates slightly upward and downward, as 
discussed above, the engraving head 1 is moved in the X and Y directions 
by the movement means (which is not shown) connected to the engraving 
apparatus (which is not shown). Letters, symbols, figures or the like are 
engraved on the engraving surface T. 
In order to produce engravings which are not expressed with a single brush 
stroke on the engraving surface T, initially, the supply of the compressed 
gas from the compressed gas supply port is brought to a released state, so 
that the gas pressure inside of inner room 3b decreases. 
Then, the slight up-and-down vibration of engraving stylus 7 stops. The 
movable body 5 moves upward energized by the flanged portion and O-ring 6 
due to the expansion of helical compression spring 8. The movable body 5 
moves upward until its peripheral portion contacts the upper surface side 
3d of movement space 3c. 
The strength of the helical compression spring 8 or the like is set so that 
the operation time of the stoppage of the supply of the compressed gas to 
the upward movement of the movable body 5 is performed within an extremely 
short time period. 
During the upward movement of movable body 5, the engraving stylus 7 also 
moves upward. In other words, the engraving stylus 7 disengages from the 
engraving surface T and tip portion 7c recedes at a sufficient distance 
from engraving surface T, as shown in FIG. 1. 
In this position, engraving head 1 is moved in the X and Y direction to a 
desired position by a movement means (which is not shown). The compressed 
gas is once again supplied from the compressed gas supply port 3a to inner 
room 3b to form the engravings which are not expressed with a single brush 
stroke on the engraving surface T. 
According to engraving head 1 of the present invention, the operation of 
the extending and contracting tip portion 7c to and from the engraving 
surface T is not performed by lifting the entire engraving head 1 upward 
and downward. In contrast, in the present invention this operation is 
implemented by the relative movement of engraving stylus 7 within body 
housing 2. Accordingly, it is not required for the engraving apparatus to 
be provided with an up-and-down movement means, such as a sliding 
mechanism or an air cylinder, for moving the entire engraving head. Thus, 
the cost and the size of the engraving apparatus may be reduced. 
Furthermore, due to the configuration of the present invention and the 
usage of the compressed gas, it is possible to rapidly move the movable 
body 5 in order to position tip portion 7c near engraving surface T. When 
the supply of compressed gas is discontinued, tip portion 7c is energized 
by helical compression spring 8 to immediately separate from engraving 
surface T. Thus, it is possible to rapidly perform a series of repetitive 
operations to smoothly produce engravings which are not expressed with a 
single brush stroke. The series of repetitive steps are: (1) positioning 
engraving stylus 7 nearby engraving surface T, (2) engraving surface T and 
(3) disengaging engraving stylus 7 from engraving surface T. With the 
present invention, these steps are performed smoothly within an extremely 
short time frame. 
It is further noted that the compressed gas can also be used as the power 
source for making the stylus 7 slightly vibrate. 
Although the present invention discloses the movement space as having a 
cylindrical space because this configuration is preferable in terms of 
frictional resistance or the like. It will be appreciated that other 
configurations may be contemplated by the invention. For example, the 
profile of the movement space may resemble a prismatic shape. Thus, the 
shape of the movable body may be modified to compliment the shape of the 
movement space. 
Likewise, although the helical compression spring is disclosed as the first 
energizing means for energizing the movable body away from the engraving 
surface, it will be appreciated that other types of devices may be 
employed as the first energizing means. 
From the foregoing description, one skilled in the art can easily ascertain 
the essential characteristics of this invention, and without departing 
from the spirit and scope thereof, can make various changes and 
modifications of the invention to adapt it to various usage and 
conditions. 
The entire disclosure of Japanese Patent Application No. 10-237793 filed on 
Aug. 24, 1998 including the specification, claims, drawings and summary 
are incorporated herein by reference in its entirety.