Screw
First Claim
1. A screw comprising:
- a shank including a tapered screw-in portion, a head portion spaced from the screw-in portion along a longitudinal axis of the shank, and a straight rod portion between the screw-in portion and the head portion;
a first thread helically formed on an outer circumference of the shank and including an upper thread portion formed around the straight rod portion, a lower thread portion formed around the screw-in portion, and a middle thread portion continuously connected between the upper and lower thread portions, with the middle thread portion formed around the straight rod portion adjacent to the screw-in portion, with a lower end of the lower thread portion extending to a tip of the screw-in portion for development of a cutting set point; and
a second thread helically formed on an outer circumference of the screw-in portion of the shank and including a plurality of thread convolutions which are spaced from thread convolutions of the lower thread portion, with a pitch of two adjacent thread convolutions of the second thread being approximately equal to a pitch of two adjacent thread convolutions of the lower thread portion of the first thread.
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Accused Products
Abstract
A screw includes a shank, a first thread, and a second thread. The shank includes a screw-in portion, a head portion, and a straight rod portion between the screw-in portion and the head portion. The first thread surrounds the shank spirally and includes an upper thread portion formed around the straight rod portion, a lower thread portion formed around the screw-in portion, and a middle thread portion continuously connected between the upper and lower thread portions. A plurality of serrate cutting teeth is provided on the middle thread portion of the first thread. The second thread is helically formed around the screw-in portion of the shank and includes a plurality of thread convolutions spaced from thread convolutions of the lower thread portion of the first thread. The screw can be quickly driven into articles to be joined without degradation of binding capacity between the screw and the articles.
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Citations
9 Claims
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1. A screw comprising:
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a shank including a tapered screw-in portion, a head portion spaced from the screw-in portion along a longitudinal axis of the shank, and a straight rod portion between the screw-in portion and the head portion; a first thread helically formed on an outer circumference of the shank and including an upper thread portion formed around the straight rod portion, a lower thread portion formed around the screw-in portion, and a middle thread portion continuously connected between the upper and lower thread portions, with the middle thread portion formed around the straight rod portion adjacent to the screw-in portion, with a lower end of the lower thread portion extending to a tip of the screw-in portion for development of a cutting set point; and a second thread helically formed on an outer circumference of the screw-in portion of the shank and including a plurality of thread convolutions which are spaced from thread convolutions of the lower thread portion, with a pitch of two adjacent thread convolutions of the second thread being approximately equal to a pitch of two adjacent thread convolutions of the lower thread portion of the first thread. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification