SCREW DRIVERS
Year: 1884

page_text: I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Engineer do hereby declare the nature of this Invention for "SCREW DRIVERS"
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The first part of this Invention relates to the combination of a helically grooved
cylinder and a screw driver shaft in such a manner that longitudinal reciprocating
motion of the cylinder will produce rotary motion in the shaft.
The second part of this Invention relates to the combination with a helically
grooved cylinder and a smooth screw driver shaft, of a rotating drive block having
a limited amount of free motion longitudinally on the screw driver shaft and
provided with projections that operate in the grooves of the cylinder; the object
of this part of the Invention being to impart intermittent rotary motion in one
direction to the screw driver shaft by means of the reciprocating cylinder.
The third part of this Invention relates to the combination of a cylinder
provided with helical grooves traversing the interior of said cylinder in opposite
directions and terminating in a recess at the end of the same, a smooth screw
driver shaft, and a drive block mounted on said shaft and provided with pivoting
projections that operate in the grooves of the cylinder; the object of this part of
the Invention being to enable the operator to adjust the cylinder to rotate the shaft
in either direction.
The fourth part of. this Invention relates to the combination with a helically
grooved cylinder and a smooth screw driver shaft, of a shaft bearing in the end of
the cylinder so constructed as to retain the lubricating oil in the cylinder.
Figure 1, in the Drawing accompanying and forming a part of this Specification,
represents this device in operation.
Fig. 2 is a longitudinal diametrical section of the same.
Fig. 3 is a longitudinal diametrical section of the cylinder.
Fig. 4 shows a portion of Fig. 3.
Fig. 5 shows the screw driver shaft and drive block.
Fig. 6 is an end view of the drive block.
a is the cylinder,
bis the handle.
t
c is the shaft bearing.
B

page_text: kare projections on shaft i.
m is the head of shaft i
n are recesses in block g.
In operation the shaft is drawn out of the cylinder as far as possible and placed
against the head of a screw; force is then applied against the end of the handle
and the cylinder made to move longitudinally along the shaft.
The cylinder has no rotary motion in its operation and consequently the drive
block is rotated by following the helical grooves.
When pressure is applied to the end of the handle, see Figure 1, the recesses of
the drive block engage projections; %, of the shaft and impart rotary motion to said
shaft on which said projections are rigid.
When the cylinder is drawn in the opposite direction the recesses of the drive
block become disengaged from the pr
projections of the shaft, the said shaft remaining
stationary while the said block rotates freely in the cylinder grooves.
It will be observed from the above description that the shaft will revolve only
when the cylinder is moved towards the screw that is being driven or drawn, and
that its motion is intermittent rotary in one direction.
It is possible, however; to reverse the direction of the intermittent rotary
motion of the shaft; thereby enabling the operator to either drive or draw a screw
by substantially the same operation, but after the necessary adjustment is effected
the motion of the shaft is, as above stated, intermittent rotary in one direction.
To change the direction of the rotating motion of the shaft, pivoting projections h
are moved into recesses f, which are located directly opposite each other, the handle
is then given a partial turn which causes the projections to swing over against the
opposite sides of the recesses in line with the reverse set of grooves, (see Figure 4
in which the two positions of the projections are indicated).
The projections h are pivoted to project in opposite directions so that while one
of the pair is crossing the intersections of the grooves, the opposite one is in the
solid part of said grooves thereby insuring smooth motion and decreasing wear.
Bearing c is provided on its inner end with a circumferential concavity that
retains the lubricating oil in the cylinder.
The double set of grooves and recess in the cylinder, and the pivoting adjustment
of the projections on the drive block enable the operator to either drive or draw a
screw.
By means of one set of grooves in the cylinder and rigid projections on the
drive block my device may be made to drive a screw satisfactorily.
Having now particularly described and ascertained the nature of this said
Invention, and in what manner the same is to be performed, I declare that what
I claim is:
1st The combination of a cylinder provided on its inner surface with a set of
helical grooves; a screw driver shaft fitted in said cylinder and provided on its
inner end with a series, of projections; and a drive block having a limited amount
of motion longitudinally on the inner end of the driver shaft, provided with
projections adapted to fit into and receive motion from the grooves of the cylinder,
and also provided with recesses adapted to engage the projections of the shaft and
impart motion thereto, substantially as set forth.
j:
2nd. The combination in a screw driver, of a cylinder provided with two sets of
helical grooves traversing its inner surface, in opposite directions and terminating
in an approximately triangular recess; a shaft provided with a series of projections
and adapted to operate in the above mentioned cylinder; and a rotating drive
block provided with pivoting projections that operate in the grooves of the
cylinder, and also provided with recesses to engage the projections on the shaft,
substantially as set forth.

page_text: 3rd The combination with cylinder a and shaft d of bearing c provided on its
inner surface with a circumferential concavity, as and for the purpose set forth.
4th The complete screw driver constructed and operating substantially as set
forth,