Machine element or mechanism – Control lever and linkage systems – Elements
Reexamination Certificate
2001-11-14
2003-10-28
Hannon, Thomas R. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Elements
C403S002000
Reexamination Certificate
active
06637287
ABSTRACT:
TECHNICAL FIELD
An improved operator handle is disclosed that is applicable to all types of windows and other applications where a cranking rotation of a handle is transmitted to one or more arms for purposes of opening and closing a structure, such as a window, hatch or door. More specifically, an operator handle is disclosed which is designed to fail in the event an excessive amount of torque is applied to the handle. Failure of the handle prevents breakage or damage to the operator which transmits the rotational movement of the handle to one or more moving arms. As a result, the handle can be easily replaced without the need for a replacing the more expensive operator.
BACKGROUND
Casement windows, louvre windows, some roof windows and a variety of doors and hatches employ a crank mechanism whereby the user cranks or rotates a handle connected to an operator. The operator, in turn, translates the rotational movement of the handle into a rotational or pivotal movement of one or more arms which results in the opening or closing of the window, door, hatch or other structure. The handles typically include a hand grip connected to a downwardly extending connecting shaft. The connecting shaft typically has a non-circular cross section such as a square or hexagon. The shaped connecting shaft is mateably received in the operator.
A typical operator design includes a worm gear with a shaped hole for receiving the connecting shaft of the handle. The worm gear is enmeshed with another gear which either directly or indirectly imparts a rotational movement to one or more arms which opens or closes the structure.
A problem arises with these conventional designs when the user applies too much force or torque to the handle. Specifically, if the window, door, latch or structure is locked and the user is unaware that the structure is locked, the user will often apply too much torque to the handle in an attempt to open the structure which can result in the worm gear being damaged or the gear enmeshed with the worm gear being damaged. Damage to the internal gears of the operator requires replacement of the operator and, often, replacement of the connecting arm or arms as well. Removal of the existing operator and installation of a new operator is a relatively time consuming and complicated procedure.
Such overtorquing by the user can also occur if the structure being opened is somehow stuck or jammed due to warping of the structure. Specifically, wooden casement window frames are prone to warping. As a result, they may not shut properly which makes it very difficult to lock the window. The user is inclined to apply too much torque or force to the handle in an attempt to shut the window completely so that the user can lock the window. This action can result in a damaged operator, which will need to be replaced. Similarly, if a window, door, hatch or other movable structure is closed for an extended period of time, it can often become stuck in the closed position due to swelling of the movable structure caused by high humidity or a bonding between the paint on the movable structure and the paint on the surrounding frame caused by moisture or heat. As a result, the user can be tempted to dislodge the movable structure by applying an excessive amount of torque to the operator handle thereby resulting in damage to the operator.
As a result, there is a need for an improved operator design with overtorque protection. In other words, there is a need for an improved operator design which effectively prevents damage to the internal components of the operator caused by an excessive amount of force applied to the handle by the user.
SUMMARY OF THE DISCLOSURE
In satisfaction of the aforenoted need, an improved handle for an operator used to translate rotational movement of the handle to at least one connecting arm is disclosed. The handle is designed to break in the event the user applies an excessive amount of torque to the handle. The improved handle comprises a hand grip connected to a connecting shaft. The connecting shaft is mateably engaged to the operator. The connecting shaft comprises at least one weakened portion that provides a failure section in the connecting shaft. The failure section is designed to break in the event an excessive amount of torque is applied to the handle. As a result, the handle breaks, instead of any of the internal gear components of the operator. The handle may then be easily replaced without the need to replace the operator.
In a refinement of the above concept, the weakened portion of the connecting shaft comprises at least one hole or recess that extends at least partially through the connecting shaft. The hole or recess causes the connecting shaft to break in the event an excessive amount of torque is applied to the handle.
In a further refinement, the at least one hole or recess comprises two diametrically opposed holes or recesses that extend at least partially through the connecting shaft.
Thus, if the connecting shaft has a hexagonal cross section, the holes or recesses are disposed in diametrically opposed surfaces of the hexagonal connecting shaft. The connecting shaft then breaks along the line that extends transversely through the connecting shaft and the holes or recesses. After the connecting shaft fails or breaks, a portion of the broken connecting shaft remains in the operator. However, the holes or recesses provide slots or a space which enables the user to obtain a grip or purchase on the broken connecting shaft so that it can be easily removed from the operator. Then, a new handle may be simply inserted into the operator.
As noted above, the weakened portion of the connecting shaft may comprise one or more holes or recesses which reduce the effective cross-sectional area of the connecting shaft in this weakened portion. The one or more holes or recesses may be in the form of one or more holes that extend into the connecting shaft transversely of the central axis of the connecting shaft. Similarly, slots or recesses may extend into the connecting shaft transversely of the connecting shaft axis. It is also anticipated that a center hole aligned with the axis of the connecting shaft would also sufficiently weaken the connecting shaft to provide a failure section. If one or more holes or recesses are employed, they need not be diametrically opposed from one another but a diametrically opposed configuration of two holes, recesses or slots is preferred.
A method for protecting an operator from being overtorqued is also disclosed. The method comprises providing a handle designed to fail when too much torque or force is applied to the handle. The handle comprises a hand grip connected to a connecting shaft. The connecting shaft comprises a non-circular cross section with at least one hole or recess extending at least partially through the connecting shaft to weaken the connecting shaft. The connecting shaft is then mateably inserted into a shaped hole of the operator.
An improved casement window operator is also provided which comprises a handle comprising a hand grip connected to a connecting shaft. The connecting shaft comprises a non-circular cross section. The connecting shaft further comprises at least one hole or recess extending at least partially through the connecting shaft to weaken the connecting shaft. The operator comprises a noncircular hole for mateably receiving the connecting shaft of the handle.
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patent: 2002/0124468 (2002-09-01), Manzella
patent: 10-280797 (1998-10-01), None
Hannon Thomas R.
Johnson Vicky A.
Roto Frank of America, Inc.
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