US3823755A

US3823755A - Geared screwdriver

Info

Publication number: US3823755A
Application number: US00354779A
Authority: US
Inventors: G Sheffield
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-04-26
Filing date: 1973-04-26
Publication date: 1974-07-16
Anticipated expiration: 1991-07-16

Abstract

A geared screwdriver having an improved mechanical advantage. The tool is provided with a gear train in driven connection with a screwdriver shank. The latter is disposed to turn within its handle. The gear train is housed in a structure which can be turned to operate the shank with the handle remaining fixed or, in the alternative, the latter may be turned to drive the shank with the housing fixed in place affording a different mechanical advantage from that which is afforded in the first mode of operation.

Description

United States Patent 1191 Sheffield 1 July 16, 1974 GEARED SCREWDRIVER 2,756,792 7/1956 Hirschman 145/50 R 145 66 [76] Inventor: George V. Sheffield, 133 Van Dyke 3580097 5/1971 van Dalen Rd., Hopewell, NJ. 08525 1 Primary Exammer-Al Lawrence Sm1th Flledi P 1973 Assistant Examiner-J. T. Zatarga 211 Appl. No.: 354,779

[57] ABSTRACT [52] 145/ 50 81/5731 2 A geared screwdriver having an improved mechanical [51 i t Cl B25) 15/02 advantage. The tool is provided with a gear train in d 61 L driven connection with a screwdriver shank. The latter 1 0 /57 3 is disposed to turn within its handle. The gear train is housed in a structure which can be turned to operate 56 R f d the shank with the handle remaining fixed or, in the 1 e erences alternative, the latter may be turned to drive the shank UNITED STATES PATENTS with the housing fixed in place affording a different 348,765 9/1886 Neal 145/50 R mechanical advantage from that which is afforded in 1,493,160 5/1924 Pierce 145/66 the first mode of operation. 1,991,766 2/1935 Matveyeff 145/61 L 2,659,255 11/1953 Bates 81/5731 X 1 Claim, 2 Drawing Figures screwdriver the shank of which is operated through This invention relates to hand tools and, in particular, to screwdrivers the shanks of which are driven through a train of gears.

The present invention contemplates a screwdriver having a rotatable shank on the end of which a gear is mounted. The gear is one of a series of spur gears, the shank being driven by a pair of said spur gears on turning the housing for the gear train or, alternatively, by the entire series of spur gears on turning the handle alone which is disposed about the shank. The separate modes of operation afford a corresponding difference in mechanical advantage.

One object of the invention is to provide an improved a gear train.

Other objects and advantages of the invention may be appreciated on reading the following detailed description of one of its embodiments which is taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of the screwdriver; and

FIG. 2 is an enlarged section taken on the line 2-2 of FIG. 1.

Referring to the drawing, screwdriver shank 4 is removably connected by means of projection 6 to the end of shaft 8. Pinned to the shaft is gear 10 in gear housing 12 having a cover 13. Disposed about the shank between the projection6 and the housing 12 is handle 14. The shaft is journalled in internal sleeve 16 integral with the handle and in plate member 18 interiorally fixed to the housing 12. Mounted on the shaft proximate the handle is ring 20 which prevents the shaft from sliding axially.

Spur gear 22 attached within the housing 12 to the end of the sleeve 16 to turn about the shaft 8 is in engagement with gear 24 of larger diameter. The latter is fixed on one .side of the member 18 to stud shaft 26 journalled in the member 18. On the other side of the member 18 is spur gear 28 mounted fixedly on the shaft 26. The gear 10 of larger diameter than the gear 28 is in engagement therewith.

In operation, if the housing 12 is held in a fixed position and the handle 14 is turned, the mechanism operates as an ordinary gear train and there results a mechanical advantage represented by a quotient wherein the product of the diameter of

gears

24 and 10 are divided by the product of the diameters of the

gears

22 and 28. On the other hand, if the handle 14 is held fixed and the housing 12 is turned, the mechanism operates as a planetary gear train having a mechanical advantage represented by the product of the diameters of the

gears

24 and 10 divided by the product of the diameters of the

gears

24 and 10 less the product of the diameters of the

gears

22 and 28.

Various modifications of the embodiment of invention as described above may be effected by persons skilled in the art without departing from any principle of invention as defined in the appended claims.

What is claimed is:

l. A geared screwdriver comprising an output shaft and a screwdriver shank afixedly connected therewith,

' shaft being journalled insaid plate member, a stub shaft journalled in said plate member, and a pair of spurgears in said gear train operative as planetary gears fixedly mounted on said stub shaft respectively on each side of the plate member, one of said spur gears engaging said output gear, said gear train including athird gear engaging the other of said spur gears, said third gear being connected to said sleeve and journalled on said output shaft.

Claims

1. A geared screwdriveR comprising an output shaft and a screwdriver shank afixedly connected therewith, a handle, a gear fixedly mounted on said output shaft, a gear train and a sleeve connected to said handle, said sleeve being internally fixed to said handle and journalled on said output shaft, said gear and gear train being disposed in a housing, a plate member partitioning the interior of said housing and afixed thereto, said shaft being journalled in said plate member, a stub shaft journalled in said plate member, and a pair of spur gears in said gear train operative as planetary gears fixedly mounted on said stub shaft respectively on each side of the plate member, one of said spur gears engaging said output gear, said gear train including a third gear engaging the other of said spur gears, said third gear being connected to said sleeve and journalled on said output shaft.