Machine element or mechanism – Elements – Cams
Reexamination Certificate
2000-01-13
2001-08-21
Luong, Vinh T. (Department: 3682)
Machine element or mechanism
Elements
Cams
C074S56800M, C074S044000, C074S571100, C074S595000, C074S600000, C074S602000
Reexamination Certificate
active
06276232
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a stroke length adjusting device, more particularly to a small-sized stroke length adjusting device, which has a rigidity more improved as compared with conventional adjusting devices, is easily manufactured and reduced an excess of torque occurred to be crank.
BACKGROUND OF THE INVENTION
As one of conventional stroke length adjusting devices may be raised a stroke length adjusting device disclosed in JP Examined Publication No. 47-33812. This stroke length adjusting device is one “which comprises eccentric shaft
1
rotated by a driving member, a member to be reciprocated by the eccentric shaft
1
connecting to the member, and an adjusting member allowing the eccentric shaft
1
to travel along the central axis XX′ thereof, characterized in that said eccentric shaft
1
is provided with rotators
52
and
53
, on which is mounted inclined shaft
51
in such a manner that both cross each other at a predetermined tilt angle &thgr; between the central axis PP′ of the inclined shaft
1
and the central axis of the rotators
52
and
53
, and a cam
2
is provided, which has hole
54
made therein so as to have said tilt angle to the central axis XX′ of said rotators
52
and
53
′ and mate said inclined shaft
51
, whereby said cam
2
is mounted through said hole
54
on said inclined shaft
51
at an angle rectangular to said central axis XX′, thus said cam
2
allowing a connecting bar
3
to reciprocate and then said eccentric shaft
1
to travel in the direction of said central axis XX′ thereof, so that the stroke length can arbitrarily be regulated regardless of whether it is operated or not”.
To be summarized, the above-mentioned stroke length adjusting device is constituted by providing the eccentric shaft
1
between the rotators
52
and
53
, which is inclined at a predetermined angle to the central axes of the rotators
52
and
53
and tightly inserted into the hole
54
provided in the cam
2
. The up-and-down movement of the rotators
52
and
53
allows the eccentric point of the cam to be changed. The connecting bar connected to the eccentrically rotated cam can be reciprocated at an arbitrarily changed stroke length by adjusting the positions in the vertical direction of the rotators
52
and
53
. The two rotators are sustained by respective cylindrical holders in such a manner that the former are mated into the latter.
However, the conventional stoke length adjusting device above has such problems as mentioned below:
(1) A load via the cam is transmitted to the rotators bound to both the ends of the eccentric shaft and then onto the cylindrical holders, in which the rotators are mated. Therefore, in order to transfer the load on the rotators to the holders, the height of the cylindrical rotators is necessary to be made larger. Furthermore, the rotators goes up and down as the eccentric shaft rises up and descends down to change the stroke length of the reciprocated connecting bar. As a result, the thick rotators move up and down at a longer distance, which makes the cylindrical rotator holders longer;
(2) Since a lubricant must be supplied to all the load-burdened positions, lubricant-supplying impellers are required at such positions;
(3) Since a large amount of the lubricant is required, an excess of the lubricant supplied may run out when the rotators are raised up;
(4) Since the structure of the two rotators between which the eccentric shaft is mounted is complicated, the fabrication or assembly thereof requires a large amount of work load;
(5) When the eccentric shaft is raised up and fallen down, a torque is burdened onto a cylindrical worm wheal in which the rotators are inserted to rotate them, and the torque-burdened position is changed as the position of the eccentric shat is moved; and
(6) Since the load applied to the cam causes components of a force to be produced on the eccentric shaft in the vertical direction thereof, a shim adjustment is required at the rotator holders to inhibit the force components in the vertical direction.
Therefore, the conventional stroke length adjusting device is complicated in the structure thereof and hence cannot be made in a small size.
The object of this invention is to solve these problems. Another object of this invention is to provide a stroke length adjusting device having a simple structure. A further object of this invention is to provide a smaller-sized stroke length adjusting device as compared with the conventional one. A still further object of this invention is to provide a stroke length adjusting device comprising a less amount of constituting elements to more easily be assembled. An additional object of this invention is to provide a sound stroke length adjusting device having an adequate strength to withstand the torque generated by the movement of the cam.
DISCLOSURE OF THE INVENTION
According to this invention, to solve the problems above, the means of this invention is a stroke length adjusting device characterized in that it is provided with a cylindrical body formed so as to be able to rotate with a rotation-driving means and rotatably held by a sustaining means, a crank member mated into the cylindrical body so as to travel in the direction of the central axis of the cylindrical body by a reciprocation-driving means, a cam mounted on the crank member in the direction rectangular to the central axis of the crank member, and a movement-converting means for converting the eccentric rotation to the reciprocation of the cam,
the crank member being inclined at a predetermined tilt angle against the central axis of the cylindrical body, thereby allowing the cam to eccentrically move as the crank member travels along the central axis of the cylindrical body and, therefore, provided with a groove-shaped cam-guiding part and further with an outer circumferential surface contacting the inner circumferential surface of the cylindrical body, and
the cam being mounted at the outside of the cylindrical body in the direction rectangular to the central axis of the cylindrical body, and provided with a part to be guided by the cam-guiding part.
In a preferred embodiment of this invention, there is provided a stroke length adjusting device, characterized in that it is provided with a cylindrical body formed so as to be able to rotate with a rotation-driving means and rotatably held by a sustaining means, a crank member mated into the cylindrical body so as to travel in the direction of the central axis of the cylindrical body by a reciprocation-driving means, a cam mounted on the crank member, and a movement-converting means for converting the eccentric rotation to the reciprocation of the cam,
the crank member comprising a first recess having a first slope inclined at a predetermined angle against the central axis of the cylindrical body and an inner wall surface facing the first slope, a second recess having a second slope inclined at the same predetermined angle but formed back-to-back with the first slope and an inner wall surface facing the second slope, and an outer circumferential surface sliding on the inner surface of the cylindrical body,
the cylindrical body comprising an inner circumferential surface contacting the outer circumferential surface of the crank member, a first opening having the same width as that of the first recess and facing the first recess, and a second opening having the same width as that of the second recess and facing the second recess, and
the cam being provided with a first projection inserted into the first opening in a mated state and having a slope end surface slidable on the first slope and a second projection inserted into the second opening in a mated state and having a slope end surface slidable on the second slope, and the cam being mounted at the outside of the cylindrical body.
In another preferred embodiment of this invention, there is provided a stroke length adjusting device, characterized in that It is provided with a cylindrical body formed so as to be able to rotate with a rot
Nagayama Eiichi
Yokomichi Manabu
Browdy and Neimark
Luong Vinh T.
Nikkiso Company Limited
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