Patent Application
20070240316
This invention relates to an improved cutter for a slat, especially a slat of a Venetian blind. In particular, this invention relates to a cutter comprising a pair of scissors, each scissor having an engagement member that cooperatively engages its opposite engagement member when the scissors are closing.
Venetian blinds are a well known covering for windows. A Venetian blind contains a number of light blocking sections in the form of slats that are designed to extend horizontally across the width of the window space. One such example of a window shade is a Venetian blind, where the light blocking sections are made of aluminum or polyvinyl chloride slats.
While window spaces are built in a myriad of different widths, Venetian blinds are typically manufactured in a number of standard widths to achieve economies of scale. To accommodate a specific window space, a standard Venetian blind must be trimmed to the particular desired width.
One way of trimming Venetian blinds is to use a scissors-style cutter adapted for cutting the slats of the Venetian blind, such as the type disclosed in U.S. Pat. No. 4,876,795. When existing cutters are used to cut slats made of particularly rigid materials such as aluminum alloys, substantial resistance is presented to the scissor blades. Since the blades are joined only at the fulcrum, this has a tendency to cause the blades to deflect outward and separate from their normal contacting engagement. Instead of cutting through the slat, the blades may slip over and bend the slat, which can cause the blades to scratch or otherwise damage the surface of the slat. This deflection makes it difficult to cleanly trim the rigid slat and results in an unsightly end product.
What is needed is an improved cutter that efficiently and cleanly trims window shades, particularly rigid slats in a Venetian blind, while minimizing any deflection of the scissoring blades by the rigid slat. The present invention meets these desires and overcomes the shortcomings of the prior art.
The present invention is an improved cutter for trimming slats, in particular for cutting the slats of a Venetian blind.
The cutter includes a pair of scissors comprising a first scissor and a second scissor pivotally joined to each other at a fulcrum. The scissors each have a jaw member portion distal to the fulcrum and a handle proximal to the fulcrum. At least one or both of the jaw members includes a blade portion that is suitable for cutting a slat as the jaw members are closing. Located at the distal end of each jaw member is an engagement member. The engagement members are adapted to cooperatively engage one another as the jaw members are closing in such a way that the engagement member of the second scissor overlaps, superimposes, or is on top of the engagement member of the first scissor to reduce deflection of the scissor blades relative to the cutting plane during the cutting of a rigid slat.
The present invention contemplates a number of engagement member configurations such as a projecting flange on one jaw member that overlaps with the distal end of the opposite jaw member, overlapping projecting flanges, or a tab and slot combination.
The improved cutter of the present invention creates a tight contact at the distal end of the cutter and consequently ensures close contact along the length of the cutting edges to reduce deflection and uneven cutting from slippage of the components during the cutting procedure.
In the drawings,
The invention disclosed herein is susceptible to embodiment in many different forms. The embodiments shown in the drawings and described in detail below are only for illustrative purposes. The disclosure is intended as an exemplification of the principles and features of the invention, but does not limit the invention to the illustrated embodiments.
Referring to
Scissors 12 and 14 of cutter 10 each have a cutting edge 22 for cutting the slat. The length of the cutting edge 22 preferably is at least as long as the standard width of the Venetian blind slat to be cut.
At the distal end 24 of the jaw members 13 and 15 is a first scissor engagement member 26 on first scissor 12 and a second scissor engagement member 28 on second scissor 14. Together, the two engagement members 26 and 28 form an engagement structure for minimizing deflection of the scissors during cutting. Engagement members 26 and 28 are adapted to cooperatively engage each other as they are closing the gap 27. As more clearly shown in
In the embodiment shown in
In this embodiment, scissors 32 and 34 are provided with projecting flanges 46 and 48 at a distal end 44. Each of the flanges 46 and 48 project towards the gap 47. The flanges 46 and 48 are offset relative to each other and have abutting surfaces 45 and 49. As the scissors 32 and 34 are moved to close the gap 47 during cutting, the flanges 46 and 48 slide over each other so that the abutting surface 45 is overlapped by the abutting surface 49. In other words, the flange 48 of the second scissor 34 overlaps on top of the flange 46 on the first scissor 32. The flanges 46 and 48 thereby block any deflection of scissors 32 and 34.
As illustrated in
Therefore, an improved cutter according to this invention provides an engagement structure at an end of the scissors that can lock and prevent deflection of the scissor blades out of the cutting plane. In a pair of conventional scissors, the scissor blades are kept in the cutting plane by virtue of the pivoting connection at the fulcrum. When a conventional scissor is used to cut a rigid object such as a slat, cutting may be inhibited by a deflection of the scissors slipping out of the cutting plane.
The cutter of the present invention alleviates this problem by creating an abutting contact between the scissors at the distal end of the cutter. This is accomplished by engaging the engagement member of the first scissor under the engagement member of the second scissor. By reversing the relative engagement of the engagement members relative to the scissor blades, i.e. the superimposing or overlapping the second scissor engagement member above the first scissor engagement member, an abutting contact is created between the first and second scissor blades. The cutter of the present invention thus prevents deflection of the blades out of the cutting plane by abutting the blade portion of the scissors at the distal end of the fulcrum.
Preferably, the engagement members engage to create this contact before the slat is cut or completely cut. More preferably, the engagement members are structured to engage each other as the scissors close and before the slat is cut. Depending on the thickness of the slats to be cut and the length of the scissor blades, the length of the projecting engagement members may vary. As an illustrative example, cutting a slat with a thickness of 2 mm with a pair of scissor blades 80 mm long may require that the engagement members project at least 8 mm along the cutting plane if the slat is initially placed 20 mm distal from the fulcrum. Similarly, cutting a thicker slat of 4 mm with the same cutter requires that the engagement member configuration span the 16 mm gap between blades at the distal end as the blades make contact with the slat when closing. It will be readily appreciated that different slat and blade length dimensions will change the distance that the engagement members must span at the distal end of the cutters in order to engage before the blades engage the slat.
The foregoing description and the drawings are illustrative of the present invention and are not to be taken as limiting. Other arrangements of the engagement structure may be implemented. For example, the engagement structure may be placed at locations other than at the tip or distal end of the scissors, such as on a portion of the scissors close to the pivotal fulcrum. The engagement structure may also be configured so that the first and second abutting surfaces overlap each other permanently. Such variations and modifications of part and embodiments are thus possible within the spirit and the scope of the present invention and will be readily apparent to those skilled in the art in view of the scope of the invention as claimed herein.
