Improvements in Clamps.
Year: 1893

page_text: Date of Application, 22nd Sept., 1893-Accepted 4th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in Clamps.
I, HERBERT KELLS, of Astoria, in the County of Queens, and State of New
York, United States of America, Manufacturer, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention relates to an improvement in clamps, and bas for its object to
provide an extension-clamp especially adapted for use in connection with articles to
be glued, cemented, or otherwise attached, and for other purposes requiring the
several parts of an article to be bound together.
A further object of the invention is to provide a clamp of light simple construction,
convenient of transportation, having no projecting ends, and which may be extended
to clamp work at least as wide again as its normal length.
Another object of the invention is to provide a clamp in which the strain will be
equalized by exerting power upon one longitudinal side upon pressure against the
opposed side, and also to provide a clamp having a perfectly straight contact
surface, whereby in panel-work or work of similar character the extra piece of wood
or metal usually employed in connection with the old form of clamp to true up the
work is dispensed with.
The invention consists in the novel construction and combination of the several
parts, as will be hereinafter fully set forth, and pointed out in the claims.
Reference is to be had to the accompanying drawings, forming a part of this
Specification, in which similar figures of reference indicate corresponding parts in
all the views.
Figure 1 is a side elevation of the clamp partially extended.
Fig. 2 is a plan view of the same.
Fig. 3 is a transverse section on line
of Fig. 1.
Fig. 4 is a perspective view of the travelling head, and
Fig. 5 is a side elevation of the sliding section.
In carrying out the invention, the body of the clamp consists of two spaced side
pieces 10 and 11, united at one end by a block 13, which is made to project
vertically downward and is widened beneath the lower edge of the body to form an
end bearing surface 14, as illustrated in Fig. 1. The ends of the side pieces at the
opposite end of the clamp are braced and united by a fixed head-block 15, the
upper end of which block is curved in the direction of the extremity of the body of
the clamp carrying the bearing block 14, as illustrated in Fig. 1, and the lower
portion of the said block is bifurcated, the members thus formed being rigidly
secured to the outer faces of the said side pieces 10 and 11. In forming the side
pieces 10 and 11 of the body, a longitudinal rib 16 is formed at or near the centre
of their inner faces, as best illustrated in Fig. 3. The said rib is provided with a
corrugation 16, said corrugation serving to reduce the friction and lessen the weight
of the clamp. The inner or sliding section 17 of the clamp consists of a strip of
wood or metal of slightly greater width than the side pieces of the body, and in the
sides of the sliding section 17 a longitudinal groove 18 is formed, in which grooves
the ribs 16 of the body section slide when the inner section is slid into the body
section, as is likewise illustrated in Fig. 3. Corrugations 17 are formed on both
sides of the sliding section 17, and said corrugations serve to lighten the weight of
said sliding section, and also reduce the friction between it and the side pieces
thereby facilitating its operation.
In each side of the inner or sliding section 17 near its top, a narrow groove 19 is
produced, and in the upper edge of this sliding section a series of curved recesses 20
are formed, producing virtually a series of teeth 21, which teeth are T-shaped in

page_text: cross-section. At the outer end of the sliding section 17 a bearing block 22 is
secured, corresponding in contour with the bearing block 14 of the body section,
and being in longitudinal alignment therewith. The central grooves are formed in
the sliding section 17 and the ribs 16 upon the side pieces of the main section, in
order that the under surface of the inner section may be carried down perfectly
flush with the under surface of the body section, and both the under surface of the
body and the inner section are made as true as possible, so that they will form a
perfect guide when the clamp is in use.
The sliding head block 23 is adapted for use in connection with the teeth 21 of
the inner section, which head is illustrated in detail in Fig. 4. The under surface
of the head, which is sufficiently wide to travel upon the upper edge of the side
pieces of the body section of the clamp, is provided with an essentially T-shaped
longitudinal slot 24, adapted to receive the teeth 21 of the inner clamp section, the
said teeth serving as a guide for the head 23 in its travel from end to end of the
clamp.
Upon the head 23, at that end facing the fixed head 15, an essentially U-shaped
latch 25 is pivoted, the bowed end of which latch is curved downward to enter the
recesses 20 between the teeth 21. The recesses 20 are each undercut at one side
wall, the opposite side wall being bevelled or downwardly curved. Thus when the
latch enters the undercut portion of the recesses it is prevented from riding upward
above the teeth. In the upper surface of the head a straining device 26 is located,
which straining device may consist of a cam-faced lever, or any device capable of
bearing against the upper surface of the fixed head 15 to force the sliding head
therefrom when the latch has been engaged with one of the recesses 20.
In the drawings the straining device employed consists of a screw having a ball 27
formed at one end, capable of entering a recess or cavity in the upper end of the
fixed head, as shown in Fig. 1, and provided at its opposite extremity with a hinged
handle 28 whereby the screw may be readily revolved.
In operation, when the two sections have been drawn apart a sufficient distance
to permit the bearing blocks 14 and 22 integral therewith to engage with the outer
edges of the work to be clamped, the latch 25 is lifted and the head 23 is slid
forward in the direction of the fixed head 15 until the latch will have engaged with
the undercut portion of the recess 20 nearest to the said fixed head. When the
latch is thus engaged, the screw 26 is turned until the ball 27 has entered the
socket in the fixed head, and the screw is then further turned, thus exerting a
tension in opposite directions upon the body section of the clamp through the
medium of the fixed head and upon the inner section through the medium of the
latch and sliding head. By this means the outer bearing blocks 14 and 22 are
made to bear firmly and securely upon the work, and when sufficient tension has
been exerted upon the latter the revolution of the screw is discontinued.
I desire it to be distinctly understood that I do not confine myself to any
particular material in the construction of the clamp. Metal, however, is preferred.
Nor do I coufine myself, as heretofore stated, to a screw for forcing the sliding
head from the fixed head when the former has been engaged with the inner section.
It will be observed that the device may be made very light, since the strain
thereon is equalized as power is exerted upon one side against the pressure brought
to bear upon the opposite side.
It will be further observed that as one section is capable of being slid into the
other section the clamp is rendered very convenient to carry, and but little material
projects beyond the extremities of the several sections.
This is a very important feature, as it often becomes necessary to produce a
hole or aperture or to do other work upon the material clamped very close to the
point where the pressure of the clamp is applied. This is very difficult to perform
when the ordinary clamp is employed; but when the clamp above described is
used any bit may be used close to the clamp, even though that bit be placed in a
bit-stock. Again, in panel work it is often necessary that the work should be
glued or cemented perfectly straight. With the old form of clamp it is usual to

page_text: use an extra bar or strip having a straight edge to contact with the work which is
clamped thereto. The use of this extra bar or strip is dispensed with when my
clamp is employed, as it matters not how far the sections may be drawn apart, the
inner or contacting face of the clamp is always perfectly straight, and a hand screw
may be placed upon the clamp at any time, if so desired.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A clamp comprising a body portion, a sliding section working in the body
portion, the said sliding section being provided with suitable bearing portions and
corrugations for reducing friction, a movable head resting upon the body portion
and engaging the sliding section, and a straining device carried by the movable
head and engaging the body portion, substantially as described.
2. A clamp comprising a body portion, said portion being provided with bearing
surfaces and corrugations for reducing the weight and friction between the body
portion and the sliding portion, a latch carrying head adapted to travel upon the
teeth of the sliding section, a bearing block secured to one of the outer ends of the
inner section and the side portion, and a straining device carried by the movable
head, substantially as shown and described.
3. A clamp comprising a body portion, a sliding section working in the body
portion, a movable head resting upon the body portion, said head carrying a latch
adapted to engage with the teeth formed on the upper surface of the sliding section,
and a straining device carried by said head, substantially as shown and described.
4. The improvements in clamps, substantially as and for the purposes hereinbefore
described, set forth, and illustrated in the annexed drawings.
Dated this 22nd day of September 1893.
F. W. BARKER,
Applicant's Agent.