GB2131114A

GB2131114A - Screw and screwdriver

Info

Publication number: GB2131114A
Application number: GB08233668A
Authority: GB
Inventors: Chung-Hsing Chang
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-11-25
Filing date: 1982-11-25
Publication date: 1984-06-13

Abstract

The improved type of slotted head screw is characterized in that it is further provided with a groove (23, 43), at the center thereof, which is deeper and less dimension than its slot (22, 42). To match this construction, a screwdriver (30, 51), is further provided with a central protrusion (32, 52) at the extremity of the wedge shaped or fluted operating end thereof. This arrangement allows better torque transmission through the existence of more points of contact between screw and driver. <IMAGE>

Description

SPECIFICATION Improved type of screw and screwdriver This invention relates to an improved screw and a tool for tightening or loosening it, more particularly, this invention concerns on a screw which may provide more contact area with the tool turning it and a specialized driving tool for attaching or detaching the same.

In the past, the screws are usually provided with slots, for example, a diametral cross slot 1 2 in their head as shown in Fig. 1 so that they can be turned by a screwdriver to penetrate through some objects in the way that the operating end 11 of the screw driver engages with the slot and transmits a torque to the screw head. When the operating end of the screwdriver enters into the slot 1 2 and applies torque, there are usually only two point of engagement which transmit the torque, and consequently, the slot of the head are inclined to deform or be caused damage due to concentrated stress.

It is a general object of the present invention to provide an improved type of screw which can furnish more torque transmitting contact area.

It is also a general object of the present invention to provide an improved screwdriver for efficiently turning a screw.

In accordance with the present invention, an improved type of screw having a stem provided with helical grooves on the surface thereof and a head provided with a slot, characterized in that the screw head is provided with a groove smaller in dimension that the slot at the end of the depth of said slot.

Advantageously, the groove of the screw according to this invention is positioned centrally in the slot.

In accordance with this invention, a screwdriver having a handle and a wedge-shaped or fluted operating end and adapted to turn a screw which has a groove provided in the slot of the head, characterized in that the operating end thereof is provided with a protrusion to fit the groove. The presently preferred examplary embodiment will be described in detail with respect to the following drawings.

Figure 1 is a schematic top view of a slotted screw head which is subjected to a twisting by a screwdriver in the prior art; Figure 2 is a top view illustrating an embodiment of the improved screw according to this invention; Figure 3 is a perspective view illustrating an embodiment of the screwdriver according to this invention; Figure 4 is a section view illustrating the operation of the screwdriver with respect to the screw, both embodied according to this invention.

Figure 5 is a top view illustrating another embodiment of the improved screw with cross shaped slotted head according to this invention; Figure 6 is a perspective view illustrating another embodiment of the screwdriver according to this invention; Referring now to Fig. 2, there is shown an improved screw head 21 having a diametral cross slot 22 in which is siturated a rectangular groove 23 which is centrally provided at the end of the depth of the slot 22. To match the unique construction of this improved screw head 21, a wedge type screwdriver 30 is thus provided with a protrusion 32 of rectangular cross-section on the operating wedged end 31 as shown in Fig. 3, whereby not only the wedged end 31 will be inserted into the slot 22 of the head in operation, the protrusion 32 provided thereon can also be inserted into the groove 23 as shown in Fig.

4 so that the contact area will be increased as well as the torque transmitted from the screwdriver will be scatteredly distributed to those areas other than concentrated.

Description will now be directed to another embodiment in accordance with this invention with referrence to Fig. 5-6. In the two figures, a cross shape slotted head screw and a screwdriver to tight or loose the same combined with the invention conception are shown respectively.

In the Fig. 5 a cross shape slotted head screw 41 is provided with, at the center of cross shape slot 42, a groove 43 in a similar way as described in Fig. 2, the groove 43 being square in its cross-section and substantially provided at the end of the depth of the intersection of two longitudinal slots that form a cross shape slot 42.

A novel flutted end screwdriver 51 is provided with a protrusion 52, at the pointed extremity of the operating end thereof, which is shaped substantially to fit the groove 43 of the slotted head 41, and thereby the flutted end of the screwdriver 51 can be engaged the slotted head 42 with more contact area to twist the slotted screw.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the inventions is not to be limited to the disclosed embodiments but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures.

1. An improved type of screw having a stem provided with helical grooves on the surface thereof and a head provided with a slot, characterized in that the screw head is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improved type of screw and screwdriver This invention relates to an improved screw and a tool for tightening or loosening it, more particularly, this invention concerns on a screw which may provide more contact area with the tool turning it and a specialized driving tool for attaching or detaching the same. In the past, the screws are usually provided with slots, for example, a diametral cross slot 1 2 in their head as shown in Fig. 1 so that they can be turned by a screwdriver to penetrate through some objects in the way that the operating end 11 of the screw driver engages with the slot and transmits a torque to the screw head. When the operating end of the screwdriver enters into the slot 1 2 and applies torque, there are usually only two point of engagement which transmit the torque, and consequently, the slot of the head are inclined to deform or be caused damage due to concentrated stress. It is a general object of the present invention to provide an improved type of screw which can furnish more torque transmitting contact area. It is also a general object of the present invention to provide an improved screwdriver for efficiently turning a screw. In accordance with the present invention, an improved type of screw having a stem provided with helical grooves on the surface thereof and a head provided with a slot, characterized in that the screw head is provided with a groove smaller in dimension that the slot at the end of the depth of said slot. Advantageously, the groove of the screw according to this invention is positioned centrally in the slot. In accordance with this invention, a screwdriver having a handle and a wedge-shaped or fluted operating end and adapted to turn a screw which has a groove provided in the slot of the head, characterized in that the operating end thereof is provided with a protrusion to fit the groove. The presently preferred examplary embodiment will be described in detail with respect to the following drawings. Figure 1 is a schematic top view of a slotted screw head which is subjected to a twisting by a screwdriver in the prior art; Figure 2 is a top view illustrating an embodiment of the improved screw according to this invention; Figure 3 is a perspective view illustrating an embodiment of the screwdriver according to this invention; Figure 4 is a section view illustrating the operation of the screwdriver with respect to the screw, both embodied according to this invention. Figure 5 is a top view illustrating another embodiment of the improved screw with cross shaped slotted head according to this invention; Figure 6 is a perspective view illustrating another embodiment of the screwdriver according to this invention; Referring now to Fig. 2, there is shown an improved screw head 21 having a diametral cross slot 22 in which is siturated a rectangular groove 23 which is centrally provided at the end of the depth of the slot 22. To match the unique construction of this improved screw head 21, a wedge type screwdriver 30 is thus provided with a protrusion 32 of rectangular cross-section on the operating wedged end 31 as shown in Fig. 3, whereby not only the wedged end 31 will be inserted into the slot 22 of the head in operation, the protrusion 32 provided thereon can also be inserted into the groove 23 as shown in Fig. 4 so that the contact area will be increased as well as the torque transmitted from the screwdriver will be scatteredly distributed to those areas other than concentrated. Description will now be directed to another embodiment in accordance with this invention with referrence to Fig. 5-6. In the two figures, a cross shape slotted head screw and a screwdriver to tight or loose the same combined with the invention conception are shown respectively. In the Fig. 5 a cross shape slotted head screw 41 is provided with, at the center of cross shape slot 42, a groove 43 in a similar way as described in Fig. 2, the groove 43 being square in its cross-section and substantially provided at the end of the depth of the intersection of two longitudinal slots that form a cross shape slot 42. A novel flutted end screwdriver 51 is provided with a protrusion 52, at the pointed extremity of the operating end thereof, which is shaped substantially to fit the groove 43 of the slotted head 41, and thereby the flutted end of the screwdriver 51 can be engaged the slotted head 42 with more contact area to twist the slotted screw. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the inventions is not to be limited to the disclosed embodiments but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures. CLAIMS

1. An improved type of screw having a stem provided with helical grooves on the surface thereof and a head provided with a slot, characterized in that the screw head is provided with a groove smaller in dimension than said slot at the end of the depth of said slot.

2. An improved type of screw as recited in claim 1, characterized in that said groove is positioned centrally in said slot.

3. A screwdriver having a handle and a wedge-shaped or fluted operating end and adapted to turn a screw which has a groove provided in the slot of the head, characterized in that the operating end thereof is provided with a protrusion in the slot of the head, characterized in that the operating end thereof is provided with a protrusion to fit said groove.

4. An improved type of screw substantially as hereinbefore described with reference to the accompanying drawings.

5. A screwdriver substantially as hereinbefore described with reference to the accompanying drawings.