Refrigeration – Means producing shaped or modified congealed product – Heat absorber with product remover
Reexamination Certificate
1997-10-01
2001-08-21
Bucci, David A. (Department: 3682)
Refrigeration
Means producing shaped or modified congealed product
Heat absorber with product remover
C074S435000, C074S437000, C074S08400R, C310S083000
Reexamination Certificate
active
06276160
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates to a motor having gears which comprises a gear mechanism such as a decelerating gear mechanism. It specifically relates to an improvement of a motor having gears, etc., with which unstable rotations of a rotor in the motor produced during start-up are stabilized in a predetermined direction.
It further relates to an ice maker using a motor having gears, which rotates at low speed and controls torque at a low level.
b) Description of the Related Art
Conventionally, there is a motor having gears which comprises a gear mechanism such as a decelerating gear mechanism and to which an AC sync motor is applied as a driving source. In such a motor having gears, the rotational direction of a rotor is not stable during start-up. In order to stabilize the rotational direction, a shading coil is added or a lever for preventing reversed rotations (as disclosed in JP Kokai S62-260541) is provided.
This conventional use of a shading coil or a lever for preventing reversed rotations brought an attendant complicated structure and also increased the number of components. This resulted in increased time required for assembling and increased manufacturing cost. In addition, a motor employing a lever for preventing reversed rotations generates a clashing noise with reversed rotations, that is, a clashing noise occurs between a projection unit of a rotor and the lever for preventing reversed rotations. This has been a problem when the motor is used in quiet circumstances.
A conventional ice maker using the above mentioned motor having gears is configured such that a boundary between ice and an ice making tray is melted by a heater provided at the ice making tray and an ice removing member is rotated to slide and drop ice from the ice making tray into an ice storage container.
Because the motor having gears includes a decelerating gear mechanism, the motor rotates at low speed and requires high torque. While the number of rotations is decreased at an output shaft portion, the torque at the output shaft is increased to rotate an ice removing member with a high torque for an infallible operation. With this, ice on the ice making tray is smoothly separated therefrom and dropped into the ice storage container.
In a conventional ice maker, however, the boundary between ice and the ice making tray is sometimes not completely melted by conducting heat from the heater at the ice making tray to melt the boundary. In addition, to simplify a switching control, one may want to actuate the motor having gears simultaneously with conducting heat from the heater. In such a case, at the beginning of rotation of the motor, regardless of the attempts of removing ice by the ice removing member, ice is not separated from the ice making tray because of the attachment of ice to the ice making tray. This results in interrupting the operation of the ice removing member. In other words, the output shaft of the motor having gears comes into a locked status (interrupted operation). Then, high torque is added to the gears in gear trains formed in the motor having gears, which may damage teeth.
Such a risk of damaging teeth is normal in a motor having gears, which requires to be rotated at low speed, because of tendency of producing high torque. For this reason, a motor having gears to which a conventional AC sync motor is applied is used in such a way that the gear is reinforced with additional cost, or, in contrast, the number of rotations is kept higher. An ice maker having a motor having gears attempts to solve the above problems by sufficiently melting ice with a heater, more precisely controlling conduction of the heater, or employing a large-size motor. These countermeasures, however, result in costing too much, decreasing efficiency in assembly, making a large device, or melting too much of the ice. On the other hand, an ice maker without these countermeasure is broken in a short period, and thus its usable life is short.
OBJECT AND SUMMARY OF THE INVENTION
The present invention is directed to providing a motor having gears in which, without having additional mechanisms or deforming the shape of a motor unit, rotations of a rotor can be controlled in a predetermined direction in a quiet manner.
Another objective of the present invention is directed to providing a motor having gears in which no extra mechanisms are added, a shape of the motor portion is not changed, rotation is at low speed, and torque is not high. Yet another objective of the present invention is directed to providing an ice maker, in which gears are not damaged even when drive members such as an ice removing member is in a so-called locked state, and a stable operation can be obtained for a long period.
In accordance with the invention, a motor having gears which transmit rotations of a rotor to an output shaft through a gear mechanism made of gear trains, comprises a gear mechanism provided with an intermittent rotation mechanism including a primary gear which rotates upon receiving rotations of the rotor and a secondary gear which meshes with the primary gear and rotates intermittently. The primary gear has a tooth unit for driving the secondary gear, a tooth-shaped hole, which is provided adjacent to one side of the tooth unit and with which a meshing tooth of the secondary gear meshes, and a control unit which is provided adjacent to the other side of the tooth unit so as to stop the secondary gear for a given period such that the primary gear is asymmetric around the tooth unit. When the primary gear rotates in a predetermined direction, the meshing tooth meshes with the tooth-shaped hole to intermittently rotate the secondary gear. When the primary gear rotates in a direction opposite to the predetermined direction, the meshing tooth contacts the control unit to stop the secondary gear and rotate the primary gear in reverse of the predetermined rotational direction.
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Nakajima Yoshihiko
Terada Yoshiaki
Tokuyuki Akabane
Bucci David A.
Joyce William C
Reed Smith LLP
Sankyo Seiki Mfg. Co, Ltd.
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