provements in Flooring Cramps and Mitre Cramps.
Year: 1894

page_text: PROVISIONAL SPECIFICATION
Improvements in Flooring Cramps and Mitre Cramps.
We JOSEPH HAMPTON, and JOSEPH HAMPTON LIMITED, all of King's
Hill, Wednesbury, in the County of Stafford, Tool Manufacturers, do hereby
declare the nature of this invention to be as follows:-
The said invention consists of the improvements hereinafter described in
flooring cramps and in mitre cramps.
In making a flooring cramp according to the said invention, we construct and
arrange the parts in the following manner. The frame of the cramp consists
essentially of a tubular case or box in which the cramping bar hereinafter
described works the said case or box having on one side a depending plate
constituting the fixed jaw of the joist clamp and having ou its other side a
depending bracket through which the screw of the movable jaw of the joist
clamp works. The upper end of the said movable jaw is provided with a headed
pin the shank of which is situated in a guide slot in the base of the case or
frame. The flooring cramp having been placed upon the joist with its fixed
jaw on one side of the said joist, the movable jaw is advanced by means of its
screw against the opposite side of the joist so as to bind the cramp thereto.
The cramping bar, which has motion at right angles to the screw of the
joist clamp, has a toothed rack on its upper side with which a pinion on a
horizontal axis passing through the tubular case or box gears. Fixed on the
said pinion axis, are two ratchet wheels having teeth in the same direction, the said
ratchet wheels being situated on either side of the tubular case or box of the
cramp. One of the said ratchet wheels has preferably about double the number
of ratchet teeth that the other ratchet wheel has and with this, the first named
ratchet wheel having fine teeth, a pawl pivoted on the outside of the case or box
of the frame engages to prevent the return motion of the cramping bar. The other
ratchet wheel is operated by a pawl pivoted to a long hand lever situated and
turning freely on the pinion axis.
When the hand lever of the cramp is turned on the pinion axis in the direction
proper to advance its pawl against the teeth of the ratchet wheel over which it is
situated, the pinion and ratchet wheels are turned through the same angle as the
operating hand lever. The pinion gearing with the rack of the cramping bar
advances the said cramping bar against the floor board to be cramped. On the
backward or return motion of the operating hand lever its pawl slides over the
teeth of the advancing ratchet wheel but the cramping bar is retained in its
advanced or cramping position by the pawl of the other or retaining ratchet
wheel until the floor board has been nailed or secured. In order to return the
cramping bar to its normal position for a second cramping operation it is only
necessary to lift the pawl of the retaining ratchet wheel and to press the released
cramping bar into its case or box.
We will now proceed to describe the improvements in mitre cramps and in order
that the said improvements may be the better understood we remark that mitre
cramps of the ordinary construction consist of a base plate or frame having on
each side an upright plate or fixed jaw the planes of the said upright plates or
fixed jaws making a right angle with each other. In a line bisecting the angle
which the said upright plates make with each other the movable jaw of the cramp

page_text: works being operated by means of a screw box on its underside travelling upon a
screw secured to the cramp so as to be capable of a rotary motion only. By the
use of this the ordinary mitre cramp the ends of the movable jaw pressing against
the inner edges of the strips of wood which it is desired to cramp, open the mitre
joint of the said strips at the inner corner and force the strips to make an angle
with each other slightly greater than a right angle.
The mitre cramp constituting part of the said invention has for its object to
remedy the defects hereinbefore referred to and consists of the following
arrangement of parts. The base or frame of the mitre cramp has a figure in plan
somewhat resembling that of a right angle triangle. In the base or frame, a
screw works for operating the movable jaw of the clutch as usual, the axis of the
said screw bisecting the right angle of the frame.
The said base or frame has on each of the sides making a right angle with each
other two uprights or fixed jaws and also at the angle an upright with a vertical
V shaped groove in it. When the cramp is in use the corner of the strips formed
by the mitre joint is introduced into the groove in the upright at the angle of the
base or frame and the two uprights referred to on each side of the frame are so
arranged that on the advance of the movable jaw against the strips to be secured
the edges of the said movable jaw meet or press against the inner sides of the
strips at a point between the said uprights. The gripping edges of the movable
jaw are inclined at right angles to each other and are serrated or roughened so as
to improve the bite on the strips. By this arrangement the opening of the mitre
joint is prevented and the strips are more securely cramped or held.
Dated this 30th day of June 1894.
W. T. WHITEMAN,
Agent for the Applicants.
We, JOSEPH HAMPTON, and JOSEPH HAMPTON LIMITED, all of King's Hill
Wednesbury, in the County of Stafford, Tool Manufacturers do hereby
declare the nature of the said invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following.
statement :-
The said invention consists of the improvements hereinafter described in
flooring cramps and in mitre cramps.
In making a flooring cramp according to the said invention, we construct and
arrange the parts in the following manner. The frame of the cramp consists
essentially of a tubular case or box in which the cramping bar hereinafter described
works the said case or box having on one side a depending plate constituting the
fixed jaw of the joist clamp and having on its other side a depending bracket
through which the screw of the movable jaw of the joist clamp works. The upper
end of the said movable jaw is provided with a headed pin the shank of which is
situated in a guide slot in the base of the case or frame. The flooring cramp
having been placed upon the joist, with its fixed jaw on one side of the said joist,
the movable jaw is advanced by means of its screw against the opposite side of the
joist so as to bind the cramp thereto.
The cramping bar which has motion at right angles to the screw of the joist
clamp, has a toothed rack on its upper side with which a pinion on a horizontal
axis passing through the tubular case or box gears. Fixed on the said pinion axis,
are two ratchet wheels having teeth in the same direction, the said ratchet wheels
being situated on either side of the tubular case or box of the cramp. One of the

page_text: said ratchet wheels has preferably about double the number of ratchet teeth that
the other ratchet wheel has and with this, the first named ratchet wheel having
fine teeth a pawl pivotted on the outside of the case or box of the frame engages to
prevent the return motion of the cramping bar. The other ratchet wheel is
operated by a pawl pivoted to a long hand lever situated and turning freely on the
pinion axis.
When the hand lever of the cramp is turned on the pinion axis in the
direction proper to advance its pawl against the teeth of the ratchet wheel over
which it is situated, the pinion and ratchet wheels are turned through the same
angle as the operating hand lever. The pinion gearing with the rack of the
cramping bar advances the said cramping bar against the floor board to be
cramped. On the backward or return motion of the operating hand lever, its pawl
slides over the teeth of the advancing ratchet wheel but the cramping bar is
retained in its advanced or cramping position by the pawl of the other or retaining
ratchet wheel until the floor board has been nailed or secured.
In order to return the cramping bar to its norunal position for a second cramping
operation, it is only necessary to lift the pawl of the retaining ratchet wheel and
to press the released cramping bar into its casc or box.
We will now proceed to describe the improvements in mitre cramps and in
order that the said improvements may be the better understood we remark
that mitre cramps of the ordinary construction consist of a base plate or
frame having on each side an upright plate or fixed jaw the planes of the
said upright plates or fixed jaws making a right angle with each other. In a
line bisecting the angle which the said upright plates make with each other the
moveable jaw of the cramp works being operated by means of a screw box on its
underside travelling upon a screw secured to the cramp so as to be capable of a
rotary motion only. By the use of this the ordinary mitre cramp, the ends of the
movable jaw pressing against the inner edges of the strips of wood which it is
desired to cramp, open the mitre joint of the said strips at the inner corner and
force the strips to make an angle with each other slightly greater than a right angle.
The mitre cramp constituting part of the said invention has for. its object to
remedy the defects herein before referred to and consists of the following
arrangement of parts. The base or frame of the mitre cramp has a figure in plan
somewhat resembling that of a right angle triangle. In the base or frame a screw
works for operating the moveable jaw of the clutch as usual, the axis of the said
screw bisecting the right angle of the frame.
The said base or frame has on each of the sides making a right angle with each
other two uprights or fixed jaws and also at the angle an upright with a vertical
V-shaped groove in it. When the cramp is in use the corner of the strips formed by the
mitre joint is introduced into the groove in the upright at the angle of the base or
frame and the two uprights referred to on each side of the frame are so arranged
that on the advance of the moveable jaw against the strips to be secured the edges
of the said movable jaw meet or press against the inner side of the strips at a point
between the said uprights. The gripping edges of the movable jaw are inclined at
right angles to each other and may be serrated or roughened so as to improve the
bite on the strips. By this arrangement the opening of the mitre joint is prevented
and the strips are more securely cramped or held.
Figure 1, of the accompanying drawings represents in side elevation, a flooring
cramp constructed according to the said invention in position on a floor joist,
and Figure 2 represents the same in plan; Figure 3 is a longitudinal vertical
section of the same and Figure 4 is a vertical cross section.
The same letters of reference indicate the same parts in Figuresto 4 both
Inclusive.
A is the base plate of the flooring cramp and a² is the depending plate, on the
one side of the cramp, constituting the fixed jaw of the joist clamp. In the
drawing the floor joist is marked B: a³ is the depending screwed bracket on
the other side of the cramp in which the screw e carrying the movable jaw b of the
+
:

page_text: joist clamp works. The moveable jaw bis guided when caused to travel by
the rotation of the screw c by the stem or neck of the headed pin 62 working in the
slot at in the base plate A (see Figure 4). On the upper side of the base plate A
is the tubular box or case a in which the racked cramping bar d is situated and
works, the head d2 of which cramping bar, when forced outwards in the way herein-
after described, bears. against and cramps the floor board to be nailed to the joist.
Crossing the middle of the tubular box or case a is a cross spindle or axis e the
middle or square portion situated in the box or case a having upon it the pinion f
gearing with the rack of the cramping bar d. The said axis e has on one side of
the case a the ratchet wheel g and on the other side the ratchet wheel h and
turning loosely on the spindle e at the side of the ratchet wheel g is the operating
lever of the cramp. The spindle e also has a fixed handle k for the purpose
hereinafter described.
The operating lever i of the cramp, turning loosely on a cylindrical part of the
axis e, has pivoted to it the advancing pawl which when the lever is raised as
indicated by the arrow n in Figure 1, engages with the ratchet wheel g and turning
the said ratchet wheel and spindle e effects through the pinion and racked portion
of the cramping bar d. the outward or advancing motion of the cramping bar d.
The said bar d is retained in the position to which it has been advanced for
cramping the floor board, while the said board is fixed by nails or screws, by the
retaining pawl lever 1, 2 which is pressed into engagement with the ratchet wheel h
by the spring m (see Figure 1). When it is wished to withdraw the cramping
bar d it is only necessary to lift the arm 2 of the lever pawl 1, 12 so as to disengage
the said pawl froin the ratchet wheel and to turn the handle k in the direction
indicated by the dotted arrow in Figure 1, when the pinion f is rotated in a
direction opposite to that by which the advance of the cramping bar & was effected
and the said cramping bar is rapidly withdrawn into its tubular case or box a.
Figure 5 represents in plan a mitre cramp constructed according to the said
invention with a portion of a picture frame cramped therein;
Figure 6 is a longitudinal vertical section through the axis of the screw, the said
screw being in elevation;
Figure 7 is a vertical section taken on the line a, a of Figure 5, and
Figure 8 is a vertical section through the line
Y, Y of Figure 5.
The same letters of reference indicate the same parts in Figures 5 to 8 both
inclusive.
A, A are the two parts or sides of the base (indicated in dotted lines in Figure 5).
at right angles to each other, on which base the two strips to be cramped and
joined are placed. The two sides A, A have the ordinary end uprights a, a and
the corner upright a² at the angle formed by the two parts A A; a³, as are the
additional or intermediate uprights or those situated at or about midway between
the end uprights a, a and the corner upright a². A is the slotted middle part of
the base in which the operating screw b is fixed and rotates, being operated by the
thumb piece or plate 62: c is the movable jaw of the cramp travelling in the slot
of the part A of the base on the rotation of the screw b. The gripping or acting
faces ², c² of the movable jaw c are at right angles to one another, that is, are
parallel to the strips d, d of the wooden frame gripped in the cramp as is best seen
in the dotted withdrawn position of the said jaw c indicated in Figure 5. The said
acting laces of the movable jaw are preferably roughened or serrated. By making
the movable jaw of the figure described and represented the strips are more securely
held in the ramp.
A movable jaw of the ordinary kind that is, with the gripping ends parallel to
one another, may be used in combination with the improved mitre cramp frame
herein before described.
By the use of the middle uprights a³, a³, supports for the strips d, d are provided
at points opposite or nearly opposite those at which the moveable jaw c operates and
the opening of the mitre joint on the screwing home of the said jaw is thereby
prevented.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that we
claim as the said invention of "Improvements in flooring cramps and mitre
cramps"
First. The construction and arrangement or combination of the parts of flooring
cramps hereinbefore described and illustrated in Figures 1, 2, 3 and 4 of the
accompanying drawings, the said flooring cramp consisting essentially of a joist
clamp supporting a tubular box or case at right angles to the fixing screw of the
joist clamp, in which tubular box or case the floor board cramping bar is situated
and works substantially as herein before described and illustrated.
Secondly. The construction and arrangement or combination of parts for
operating the cramping bars of flooring cramps hereinbefore described and
illustrated in Figures 1, 2, 3 and 4 of the accompanying drawings; that is to say,
the use of a spindle or axis crossing the tubular box or case in which the cramping
bar works, the said spindle having upon it a pinion for gearing with a rack on the
said cramping bar, the said cross spindle also being provided with two ratchet
wheels with one of which the advancing pawl on the operating lever (which turns
loosely on the cross pinion spindle) engages; a spring pressed retaining pawl
engaging with the other ratchet wheel substantially as and for the purpose herein-
before described and illustrated; the rapid withdrawal of the cramping bar being
effected preferably in the way described and illustrated.
Thirdly. In mitre cramps of the kind hereinbefore described and illustrated in
Figures 5, 6, 7 and 8, the use of intermediate uprights a³, as for supporting the
strips at points opposite or nearly opposite those at which the movable jaw grips
the said strips substantially as herein before described and illustrated, whether the
said additional uprights be used in combination with a gripping jaw constructed
according to this invention or with an ordinary gripping jaw.
Fourthly. In mitre cramps of the kind herein before described and illustrated in
Figures 5, 6, 7 and 8 of the accompanying drawings, making the gripping or acting
faces of the movable gripping jaws at right angles to each other so as to obtain an
increased surface grip on the strips cramped substantially as herein before described
and illustrated.
Dated the Eighth day of March 1905
JOSEPH HAMPTON.
JOSEPH HAMPTON LIMITED,
By WILLIAM HAMPTON,
Director.