U.S. patent number RE33,733 [Application Number 07/289,365] was granted by the patent office on 1991-11-05 for device for driving a drilling and/or impacting tool.
Invention is credited to Wilhelmus J. M. Hendrikx, Jan P. Houben, Antonie J. Moolenaar.
United States Patent |
RE33,733 |
Hendrikx , et al. |
November 5, 1991 |
Device for driving a drilling and/or impacting tool
Abstract
A device for driving a drilling and/or impacting tool including
a shaft journalled in a housing so as to be rotatable, if
necessary. One end of the shaft is connectable with the tool
whereas the other end is accessible for an oscillatory impact body
movable in the housing by a guide, a rotatable driving shaft
setting and a transmission. The transmission includes a device for
converting the rotary movement of the driving shaft into an
oscillatory movement of a driving element which is connected
through an elastic member with the impact body.
Inventors: |
Hendrikx; Wilhelmus J. M. (4838
Ev Breda, NL), Moolenaar; Antonie J. (4949 An Dorst,
NL), Houben; Jan P. (4834 Lv Breda, NL) |
Family
ID: |
19842771 |
Appl.
No.: |
07/289,365 |
Filed: |
December 22, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
673617 |
Nov 21, 1984 |
04726430 |
Feb 23, 1988 |
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Foreign Application Priority Data
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Nov 24, 1983 [NL] |
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8304043 |
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Current U.S.
Class: |
173/109; 173/122;
173/202 |
Current CPC
Class: |
B25D
11/062 (20130101); B25D 11/005 (20130101); B25D
16/003 (20130101); B25D 2217/0015 (20130101); B25D
2250/381 (20130101) |
Current International
Class: |
B25D
11/00 (20060101); B25D 16/00 (20060101); B25D
11/06 (20060101); B23B 045/16 () |
Field of
Search: |
;173/13,48,109,117,118,119,120,121,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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296710 |
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Nov 1915 |
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DE2 |
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499505 |
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Mar 1930 |
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DE2 |
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910160 |
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Mar 1954 |
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DE |
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2048753 |
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Dec 1980 |
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GB |
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2058645 |
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Mar 1981 |
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GB |
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Primary Examiner: Yost; Frank T.
Assistant Examiner: Fridie, Jr.; Willmon
Attorney, Agent or Firm: Jones, Day, Reavis & Pogue
Claims
What is claimed is:
1. A device for driving a drilling and/or impacting tool
comprising:
a tool shaft journalled in a housing so as to be rotatable, if
necessary, one end of said shaft being connectable with the tool
whereas the other end is accessible for engagement with an
oscillatory impact body movable in the housing by means of a guide
and a rotatable driving shaft operatively connected through a
transmission for impacting rotation to the tool shaft and/or
movement to the impact body against the tool shaft, characterized
in that the transmission comprises means for converting the rotary
movement of the driving shaft into an oscillatory movement of a
driving element, which is connected through an elastic member with
the impact body, said elastic member has a non-linear spring
characteristic.
2. A device as claimed in claim 1, characterized in that the
elastic member is a metal spring.
3. A device as claimed in claim 1, characterized in that the
elastic member is formed by at least one leaf spring.
4. A device as claimed in claim 3, characterized in that the
driving element comprises a supporting arm extending along the
curved leaf spring, said driving element being pivotally journalled
in the housing.
5. A device as claimed in claim 4, characterized in that a
supporting arm is provided on each side of the leaf spring.
6. A device as claimed in claim 4 characterized in that the or each
arm is made from elastic material having a spring characteristic
curve differing from that of the leaf spring.
7. A device as claimed in claim 1 characterized in that at the end
remote from the tool shaft is provided with a sliding guide for the
impact body extending away from said end.
8. A device as claimed in claim 1, and further including pivotol
arms.Iadd., .Iaddend.said guide for the impact body .[.is.].
.Iadd.being .Iaddend.formed by one or more of said pivotol
arms.
9. A device as claimed in claim .[.1,.]. .Iadd.8
.Iaddend.characterized in that said elastic member is arranged
between said .[.motion converting means.]. .Iadd.means for
converting the rotary movement .Iaddend.and said pivotol arm of the
impact .Iadd..[.mass.]. .Iaddend..Iadd.body. .Iaddend.
10. A device according to claim 9, characterized in that said
elastic member is formed as a pair of leaf springs, the outer ends
of which are diverging from each other, said diverging outer ends
being taken up in an orifice of said pivotable arm.
11. A device as claimed in claim 10, characterized in that a
support strip is arranged in between said pair of leaf springs.
12. A device as claimed in claim 1, characterized in that said
transmission is provided with coupling means to connect the motion
converting means to said driving shaft.
13. A device as claimed in claim 12, characterized in that said
coupling means is a claw-coupling, one part of which is axially
slidable upon an intermediate shaft of said transmission, said
sliding movement being derived from said impact body imparting a
shafting motion to said tool shaft.
14. A device for driving a drilling and/or impacting tool
comprising:
a housing,
a shaft journalled in said housing for rotation and for
reciprocation, said shaft having a first end projecting from said
housing and a second end being disposed within said housing;
an oscillatory impact body being operatively disposed within said
housing adjacent to said second end of said shaft;
a guide for guiding the movement of said oscillatory impact
body;
a rotatable driving means for imparting rotation to said shaft;
transmission means for converting rotation of the rotatable driving
means into an oscillatory movement; and,
an elastic member having a non-linear spring characteristic
connected to said housing for restraining said impact body during
oscillation, said elastic member includes a leaf spring selectively
engageable with an arm for controlling the spring character of said
leaf spring. .Iadd.
15. The device according to claim 9 characterized in that said
elastic member comprises a support strip and at least one leaf
spring. .Iaddend. .Iadd.16. The device according to claim 15
characterized in that the leaf spring has a fixed end and a distal
end which progressively diverges from said support strip when said
leaf spring is in its relaxed state. .Iaddend. .Iadd.17. The device
according to claim 9 characterized in that said elastic member
comprises a support strip arranged between a pair of leaf springs,
means for fixedly securing corresponding ends of said strip and
said leaf springs to said housing, the distal ends of said leaf
springs progressively diverging from said support strip when said
leaf springs are in their relaxed state. .Iaddend. .Iadd.18. The
device according to claim 17 characterized in that said motion
converting means engages said leaf springs adjacent the distal ends
of the latter. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for driving a drilling and/or
impacting tool comprising a shaft, which is arranged, if necessary,
in a rotatable manner in a housing, and one end of which is adapted
to be fastened to the tool, whereas the other end is accessible to
an oscillating impact body which is movable by means of a guide in
the housing, whilst a rotatable driving shaft through a
transmission can be set for moving the tool shaft and/or the impact
body.
2. Description of Background Art
A device of the kind set forth in the preamble, also known by the
term of rotohammer, impact drilling machine or hammer drilling
machine is in general provided with an impact body arranged in a
cylindrical guide. The impact body is freely reciprocatable as a
piston in the cylinder, and the drive is performed by a main piston
arranged at the bottom of the cylinder and being driven by a motor
in an oscillatory manner. As a result of the pressure differences
between the two pistons a free impact effect is produced on the one
hand on the tool shaft, whereas on the other hand impact contact
between the main piston and impact body is avoided by the air
cushion, which may be regarded as being a progressively operating
air spring. Therefore, this spring represents the reversal of the
direction of movement.
Such devices are, however, fairly complicated in construction and
due to the freedom of movement of the impact body the required
impact frequency cannot be attained at all numbers of revolution.
Moreover, due to the adiabatic compression in the cylinder cinetic
energy loss occurs apart from friction loss due to the required
seals, which becomes manifest in heat and wear.
SUMMARY AND OBJECTS OF THE INVENTION
The invention has for its object to obviate the aforesaid
disadvantages and provides to this end a device which is
distinguished in that the transmission is provided with means for
converting the rotary movement of the driving shaft into an
oscillatory movement of a driving element, which is connected
through an elastic member with the impact body. The elastic member
preferably has a non-linear spring characteristic curve.
Thanks to the steps described above the impact body will lag with
respect to the elastic element because of the interposed elastic
member, whilst in addition the kinetic energy can be flexibly
picked up and transferred to the optimum to the tool shaft.
In one embodiment the elastic member is a metal spring, preferably
a leaf spring, which simplifies the construction.
In order to render the leaf spring progressively operative, so that
an ideal reversal of the kinetic energy of the impact body is
obtained, the driving element comprises a supporting arm extending
along on both sides of the leaf spring, which element with the leaf
spring is pivotally journalled in the housing. Owing to the
oscillatory pivotal movement of the element the leaf spring
extending along the supporting arm will develop along the
supporting arm so that the desired progressive effect is obtained.
The supporting arm serves, moreover, as a load inhibitor for the
leaf spring.
In a further embodiment of the device in accordance with the
invention the other end of the tool shaft is provided with a
sliding guide for the impact body directed towards said end in
order to ensure the correct impact effect. In a further embodiment
the guide is constructed in the form of a pivotal mechanism.
BRIEF DESCIRIPTION OF THE DRAWINGS
The invention will be described more fully with reference to a
number of embodiments.
The drawing shows in:
FIG. 1 an axial sectional view of part of a transmission part of a
device embodying the invention,
FIG. 2 a perspective view of part of the transmission device,
FIGS. 3 and 4 an axial sectional view like FIG. 1 and a perspective
view like FIG. 2 respectively of a second embodiment,
FIG. 5 an axial sectional view like FIG. 1 of a third
embodiment,
FIGS. 6 and 7 each an axial sectional view like FIG. 1 of two
alternative embodiments of the elastic member and
FIG. 8 an axial sectional view like FIG. 5 of a fourth
embodiment,
FIG. 9 an axial sectional view like FIG. 3 of a fifth embodiment,
provided with a coupling means,
FIGS. 10, 11 and 12 a perspective view, front view and side
elevational view respectively of a part of the transmission device
of a sixth embodiment,
FIG. 13 a perspective view like FIG. 10 of a part of the
transmission device in a seventh embodiment,
FIG. 14 a elevational sectional view according to line XIV--XIV in
FIG. 13,
FIG. 15 a cross-sectional view according to XV--XV in FIG. 14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiment shown in FIGS. 1 and 2 of the foremost part of a
drilling and/or impacting device mainly comprises a tool shaft 1
provided at the left-hand end as viewed in FIG. 1 with means for
receiving the tool holder 2 in which a tool can be arranged in
known manner.
The tool shaft 1 is rotatable by means of bearings 3, 4 in the
hub-shaped part 5 of a housing 6 and freely displaceable over a
given axial distance. The other, opposite end of the tool shaft 1
is provided with a fixedly secured gear wheel 7, which co-operates
with a pinion 8 of an intermediate shaft 9. The intermediate shaft
9 is journalled in the housing 6 by means of the bearings 10 and
11. The intermediate shaft 9 is furthermore provided with a gear
wheel 12 co-operating with a pinion 13 on a shaft 14, which is
driven by a motor or the like (not shown).
The intermediate shaft 9 is provided at the side of the gear wheel
12 with an eccentric sleeve 15, which is surrounded through a
bearing 16 by a ring 17. The ring 17 is coupled with a second ring
18 holding a universal bearing 19. The universal bearing 19 is
connected with a pin 20 which is rigidly secured at the end remote
from the bearing to an element 21 directed transversely to the
intermediate shaft 9 and provided at both ends with bearing stubs
22 rotatably journalled in the housing 6.
The element 21 is connected with a mainly U-shaped leaf spring 23,
the limbs of which go over to curved end pieces 24, which surround
bearing stubs 25 of an impact body 26.
The impact body 26 has a given mass depending on the type of
machine and has a central hole through which passes a pin 27
registering with the tool shaft 1.
The element 21 has furthermore arms 28 rigidly secured thereto and
extending upwards from the element 21 along the limbs of the leaf
spring 23.
The device described above operates as follows.
The inwardly projecting hub 5 is equipped at the end facing the
impact body with a buffer 29, which limits the free displacement to
the left of the tool shaft 1 and which damps the percussion energy
in the no-load state.
By rotating the driving shaft 14 the intermediate shaft 9 and the
tool shaft 1 are set rotating through the transmission formed by
the gear wheels 7, 8 and 12, 13.
Owing to the rotation of the intermediate shaft 9, the ring 17 and
the ring 18 respectively will move up and down owing to the
eccentric sleeve 15. The upward and downward movement of the ring
18 is transformed into a swinging movement of the driving element
21 about the bearing journals 22 thereof. This swinging movement is
transferred to the leaf springs 23 as well as to the arms 28.
Therefore, the leaf springs 23 will slide the mass 26 to and fro
along the pin 27, whilst at each backward movement and the
subsequent forward movement the leaf spring 23 more or less
intimately engages the arm 28.
With a more intimate engagement the rigidity of the leaf spring 23
increases so that a progressive spring effect is obtained. The
progressive spring effect contributes to a uniform reversal of the
direction of movement of the impact body 26 so that the kinetic
energy is transferred to the inwardly projecting end of the tool
shaft 1 practically without development of heat and with maximum
efficiency.
FIGS. 3 and 4 show an embodiment in which the transmission members
and the complete disposition of the shafts correspond to the
embodiment of FIG. 1. Therefore, the same reference numerals are
used.
The difference of this embodiment resides in the lack of the axial
pivot guide 27, which is replaced by two pivot arms 50, which are
pivotally journalled about a shaft 51 below in the housing. The
shaft 51 is held in supports 52 rigidly secured to the housing. The
free end of each arm 50 is fastened by screws 53 to the impact body
26. About the same shaft 51 is furthermore pivotable the elastic
member formed by a leaf spring 23, a curved top end of which grips
around lugs 25 of the impact body 26 in the manner described above.
The tilting movement of the leaf spring 23 results through the same
transmission from the driving shaft 14 as described with reference
to FIG. 1.
It should be noted that in the neutral position the leaf spring 23
does not have a curved shape and is provided on both sides with
supporting arms 28, 28', which diverge in upward direction. Also
these supporting arms provide by their predetermined curvature a
progressive spring effect, whilst the impact body 26 describes an
arcuate path, the centre of rotation of which is the shaft 51.
Thanks to the independent swinging motion of the leaf spring
.[.25.]. .Iadd.23 .Iaddend. with respect to the arm 50 the impact
body 26 will lag with respect to the motion of the leaf spring
.[.25.]. .Iadd.23. .Iaddend.With a correct proportioning the full
percussion energy concentrates on one end of the tool shaft 1.
The tool shaft 1 is provided with a gear wheel 7 rigidly secured
thereto and the free axial movement of the shaft 1 is limited by a
sleeve 54 arranged between the outermost bearing 3 and the gear
wheel 7.
The buffer 29 for absorbing the percussion energy in the idle state
of the tool shaft 1 is fastened in this case to an intermediate
wall 55 of the housing 6.
FIG. 5 shows an embodiment in which the impact mechanism
corresponds with respect to its component parts to the embodiment
of FIG. 3, the difference being that the rocking pin 20 is directed
to the front away from the means 17, 18.
In this embodiment the tool shaft 1 is provided at the side of the
driving gear wheel 7, which is now directly driven by the motor
shaft 14, with a pinion 60, which co-operates with a gear wheel 61
secured to an intermediate shaft 62 journalled in the housing 6.
The intermediate shaft 62 is equipped with an axially extending
eccentric pin 63, which extends in a bearing 16 of the transmission
means imparting to the pin 20 a tilting movement about the shaft
51. In this embodiment the leaf spring 23 is arranged on the tool
side of the fixed pivotal arms 50, but the mode of operation
corresponds with that of FIG. 3. In this embodiment a particular
impact effect can be obtained in which the percussion tool, for
example, a drill occupies each time one or more angular positions
at the instant when the impact body 26 strikes the tool shaft 1.
When the transmission ratio of the gear wheels is 1:1, the tool
will each time occupy a single angular position.
FIGS. 6 and 7 each show an alternative embodiment of spring
elements. In the figure the same reference numerals are used for
the corresponding elements of FIGS. 1 and 2.
The leaf spring 23 is replaced here by a body 30 of elastic
material which is vulcanized on the one hand to the impact body 26
and on the other hand to the plate 31. The plate 31 is connected
with an arm 32 corresponding with the arm 28 and guiding to the
driving body 21.
The elastic body 30 is made from a material such that the
progressive effect is ensured. The body may be porous or may have
more or less cavities in order to obtain said progressive
effect.
FIG. 7 shows an embodiment in which the spring element is formed by
a helical spring, the turns of which exhibit decreasing radii of
curvature. The thickness of the material or the variation in radius
of curvature is such that again a progressive spring effect is
ensured.
The two embodiments of FIGS. 6 and 7 operate like the embodiments
described with reference to FIGS. 1 and 2.
FIG. 8 shows an embodiment in which the means for converting the
rotary movement into a reciprocatory movement are formed by an
eccentric 70 comparable to the ring 17 of the preceding figures,
the outer ring forming in this case, in addition, the driving
element. With this ring element is coupled one end of an elastic
member formed by a spring 71, the other end of which is connected
with a stem 72 of an impact body 73. The stem 72 and the impact
body 73 rigidity secured to the former are pivotable about the
shaft 51 and journalled in the housing 6.
The embodiment according to FIG. 9 is substantially similar with
the embodiment of FIG. 3 and the same reference numerals are used
for the same parts. In this embodiment the ring 17 is provided with
a bearing hub 90 engaging a pivot pin 91 rigidly secured in the
pivot body 50'. This pivot body 50' is comparable with the pivot
arms 50 in FIG. 3. The body 50' is pivotally journalled about a
shaft 51 in the lower portion of the housing 6. The shaft 51 is
held in supports 52 rigidly secured to the housing.
Furthermore the eccentric sleeve 15 is at the side face provided
with a part of a claw-coupling 92, which co-operates with a second
part 93, which is slidably to and fro of the coupling.
The movable coupling part 93 is provided with a sleeve-like
extension 94, fitting over the pinion 8 of the intermediate shaft
9. The end face of the sleeve 94 abuts the side face of the gear
wheel 7 of the tool shaft 1.
The mechanism of FIG. 9 operates as follows:
When pushing the tool against a work piece the shaft 1 will be
urged inwardly in the housing 6, so shifting the gear wheel 7 to
the right in FIG. 9. When shifting the gear wheel 7 the sleeve 94
will also be shifted to the right, whereupon the coupling part 93
will contact the coupling part 92 so establishing a connection
between the intermediate shaft 9 through pinion 8, sleeve 94 to
eccentric sleeve 15. So rotating the shaft 9 the eccentric sleeve
15 will cause an upwards and downwards movement of the hub 90 and
shaft 91, whereupon the swing body 50' will swing around pivot axis
51. Since the spring blades 23 are rigidly secured to the pivot
body 50', and the mass 26 is also rigidly secured to the leaf
springs 23, a swinging movement of the body 50' will cause a
swinging movement f the mass 26, which will hit the end face of
tool shaft 1, since this face protrudes in a rearward position
beyond the buffer 29 of the housing 6. As soon as the work piece is
left the helical spring in between the coupling parts 92, 93 will
urge the sleeve 94 to the left in FIG. 9, so stopping the
percussion action of the mass 26 upon the end face of shaft 1,
since the connection of eccentric sleeve 15 to the intermediate
shaft 9 is broken.
In the FIGS. 10, 11 and 12, showing a sixth embodiment of the
invention the same reference numerals are used for the same
elements described hereabove.
The impact mass 26 is rigidly secured to pivot arms 50, which are
pivotally journalled about a shaft 51 below in the housing, whereas
the shaft 51 is held in supports 52 of the housing. The structure
is substantially similar to the structure in FIGS. 3 and 4.
The intermediate shaft 9 is also provided with an eccentric sleeve
15 bearing a ring 17, corresponding to a structure as shown in FIG.
9.
However the ring 17 is provided with a U-shaped bracket 100 at its
lower side.
The U-shaped bracket 100 is further provided with two stubs 101,
102 arranged vertically above each other. A certain distance is
left between the stubs 101, 102. The elastic member is formed by a
pair of leaf springs, extending parallel to the axis 51 and through
the nip of the stubs 101, 102 up to an orifice 103 in each pivot
arm 50. In between the leaf springs 23' a strip 28' is arranged,
which strip is comparable with the arms 28 in FIG. 1, 3 and 9. In a
neutral position the leaf springs 23' are in contact with the strip
28' in the middle area near the stubs 101, 102, whereas the leaf
springs are curved upwardly and downwardly respectively near their
outer ends. Said outer ends are in contact with the edges of the
orifice 103.
The transmission as shown in FIG. 10-12 operates as follows. When
rotating the intermediate axis 9, the eccentric sleeve 15 will urge
the ring 17 in a down- and upwards movement so taking along the
bracket 100 and stubs 101, 102 as well. So the middle area of the
spring leaf set 23', 28' are moved up- and downwardly which
movement will cause a swinging movement of the arms 50 and impact
mass 26 as well. During the upwards movement of the bracket 100,
the top leaf spring 23' will become more and more in intimately
contact with the strip 28'. When moving downwards the lower leaf
spring 23' will contact the strip 28' more and more, so increasing
the rigidity of the leaf spring 23' so that a progressive spring
effect is obtained.
It is to be noticed that the hammering action of the impact mass
26, can be optimized by altering the distance between the leaf
spring set 23' and the pivot axis 51. Thereto special arrangements
can be made to displace the pivot axis 51 with respect to the swing
arms 50 and/or to enlarge the orifice 103 to be able to shift the
spring set more or the less in the direction of pivot axis 51.
Those arrangements are not shown but it should be clear for every
person skilled in the art.
It is obvious that the transmission shown in FIGS. 10-12 can be
provided with an coupling means as taken up in the transmission of
FIG. 9.
Turning now to FIGS. 13, 14 and 15 it appears that a similar set of
leaf springs 23' and intermediate strip 28" are used in the
transmission shown. It is noted that in these figures the same
reference numerals are used for the same elements. The spring set
is however arranged parallel to the intermediate axis 9, so
perpendicular to the spring set in FIG. 10. Such an arrangement has
the advantage that the total space necessary to mount the different
elements of this structure is diminished. The leaf spring set is
fixedly secured in a support 110 of the housing 6. The ring 17
around the intermediate shaft 9 is provided with a bracket 111,
having a through-hole 112, see FIG. 15. The spring set 23", 28" is
let through said hole 112 and through a orifice 113 of the pivot
body 50. The orifice 113 has a width able to take up the outwardly
curved outer ends of the leaf springs 23" and the strip 28" as
well.
.Iadd.As shown in FIGS. 13-15, the elastic member comprises a
support strip 28" mounted between the leaf springs 23".
Corresponding ends of the support strip and the leaf springs are
fixed to the housing by the bracket 110. The distal ends of the
leaf springs 23" progressively diverge from the support strip when
they are in the relaxed state as shown in FIG. 14. Thus, the
progressive or non-linear spring effect is achieved. As will be
observed from FIGS. 13 and 14, the motion converting means",
engaged the leaf springs adjacent their distal ends..Iaddend.
The operation of this transmission is similar to the operation of
the transmission according to FIGS. 10, 12, since a rotation of the
intermediate shaft 9 will give an up and downwards movement to the
bracket 111 and the middle area of the spring set 23". The up and
down moving end portions of the leafs 23" will cause an swing
movement of the pivot body 50 around pivot shaft 51, and so a
swinging movement of the impact mass 26. The transmission is
provided with a claw-coupling mechanism as described in FIG. 9.
The invention is not limited to the embodiments described above.
For example, the transmission between the various shafts may
comprise more than one pair of gear wheels.
* * * * *