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Octe 1, 1946.
|_. A. ISPIEVAK
ADJUSTABLE HOLD-DOWN DEVICE
Filed March 29, 1943
' 2,408,586
2,408,586
Patented Oct. 1, 1946
Louis A. vSpievalr, WestLos AngelesjGalifeg l’ V '
Application March 29, 1943, SerialNo. 480313 '
1 Claim;
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(01.,144i290)
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My invention relates to hold-down devicesand
which the ‘adjustment ‘may be readily made to
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dispose a clamping bar in a‘ desired position and
has‘particular reference tea-device to be secured
thereafter the foperation of ‘the clampingibar to
clamping position willalwa'ys dispose the clamp
‘upon or attached to a work table to engage and
hold workpieces down upon the table in a desired
ing bar in the adjusted position.
position to permit the performance of manufac
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' Another’ object? of fmy'i invention is ‘to provide
turing operations upon such workpieces.
"a. hold-down'deviceo'f the character ‘described
wherein the adjustment may be'altered “from time
time or_'th_e clamp may be ‘adjusted initially
ufacture (large quantities’ of identical parts by to‘
‘building jigs to be associated with variousymaé 10 to a 'desired'lpo'sition' and the adjustment is'then
permanently ?xed.’ ‘
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chines’which are to perform manufacturing oper
' Other objects’andadvantageslof my invention
ations upon these parts to locate the parts on the
will be apparent from a'study of the following
machine in a. desired position for the perform
speci?cation, read in connection with the ‘accom
ance of such manufacturing operations. "The
I In industries such asfautomobileand aircraft
manufacturing it is the common practice to man
problem which is presented is to'hold the various 15
workpieces in position in the jigs or upon desig- I
e
_
Fig. 1 is a perspective viewof an adjustable
hold-down device constructedin ‘accordance with
nated portions of a work table of the machine,
with assurance that the workpiece will not be
panying drawing, wherein?
- my invention;
Fig. 2 is aside élevational View, partlyin sec}
readily displaced ‘from thedesired position dur
ing the performance of the work. For this pur 20 tion, of thezfhold-downidevice shownin'Fig. I};
Fig. 3' an end elevationalwview of the ‘hold
pose various types of hold-down devices or quick
down device illustrated in Figs. 1 and 2;
acting clamps have been devised,’ a typical exam;
v‘ Fig. 4 is?a side "elevationallview of the hold‘
ple being that shown in my cope‘ndingv applica
down deviceillustrated in Figs. l through 3, and
tion Serial No. 405,964, ?led August 8, 1941. The
illustrating the position‘ of the clampingbar and
common characteristic of these hold-down de- . 25
:
handle
whengvthevclamping bar is in its'released
vices is the use of a bar or workpiece engaging
or non-working position;
member which is held in a clamped position on
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I Fig. 5 is a sideelevational View of a modi?ed
the workpiece by means of cams or toggle joints
by which a handle may readily move the clamp
ing bars into and out of engagement with the ‘
workpiece and to hold the clamping’ bars inth'eir
type of adjustable hold-down device embodying
mylinventionjand
Fig. 6.is a front view,‘par_t_ly_in
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section,
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w of the
hold-down device illustrated in ,Fig. '5. .,
clamping positions without .the ‘necessity of ‘em
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I, Referring to the drawing, I have illustrated
. Fig.1 a typical hold-down devicevconstructedrin
I Heretofore the clamps or hold-down devices .35 accordance with my.’ invention as comprising a
pair of. supp'ort'members I and 2 which maybe
have been speci?cally designed to disposethl
constructed ‘as angular brackets: having, verti
clamping bar a predetermined distance away from
cally extending portions 3 and 4, respectively,
the work table whenever it is in its clamped posi
and horizontally extending foot portions 5 and 6,
tion; requiring either the use .of spacing blocks
ploying additional looking or holding mecha
nisms.
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respectively. The foot portions 5 and .6 are
adapted to be secured to the surface of a work
I between the workpiece and the table or between
the clamping bar and, the workpiece if the thick
ness'of the workpiece ‘does not coincide with the
predetermined distance between the clamping
table or tothe' work supporting surface of a
machine which is to be usedto perform a manu
facturing operationupon a workpiece. The se
bar and the work table for which a clamp or
45 curing of the feet 5 and'? may be accomplished
holdedown device has-been speci?cally designed. Iv _
_It is therefore an object of my invention to “ ‘ in any desired manner ‘such as by welding the "
provide va hold-down of the type described, in
which thedistance between the clamping bar
and the work table when the clamping bar is
in working or clamping position may be'readily
feet directly to the work table or work supporting
surfaces.
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each other a suii‘icient distance to permit
50 from
the interposition therebetwee'n of a clamping bar
adjusted to adapt the hold-down device to work;- ~ -
pieces of anin?nite numberof differentcthick
7
‘The supports "I and '2 are spaced horizontally
‘I pivoted to the supports ‘I and 2 by means of a
pivot pin 8 so‘ as to permit ‘the clamping bar to
be moved fromv its horizontally extending posi
Another object of my invention is to. provide
tion, as shown in Fig. 1, to asub'stantially verti
55
a hold-down device of the class described,’in
nesses.
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2,408,586
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cally extending position, as shown in Fig. 4. The
clamping bar 1 constitutes a lever fulcrumed at
its pivot pin 8, the opposite end 9 of the bar ‘I
would be possible with the clamping bar in its
cated at !3 to the handle Ill and also pivoted
upon a bolt l4 adapted to extend through match
Once the bolt l4 has been shifted su?iciently
to make the working position of the clamping
ing slots 15 in the supports l and 2.
The form of handle shown in Figs. 1 through 4
is generally that of a bellcrank, the longer lever
of the bellcrank constituting the direct handle
portion to be engaged and manipulated by the 15
bar 1 adapted for a particular thickness of work
piece, the nut l6 may be tightened with assurance
that upon each operation of the handle 10 the
clamping bar will move to the new working posi
horizontal position. Likewise shifting the bolt
forwardly in the slot IE will dispose the working
being connected to a handle In as by means of a
position of the outer end of the clamping bar at
pivot pin or rivet l l by which the handle and bar Oi a, greater distance away from the work table, such
may rotate relative to each other.
as isshown in the dash line position indicated
The handle Ill is supported upon the supports
at [8 in Fig. 2', thus accommodating the clamp to
l and 2 as by means of a link l2 pivoted as indi
workpieces of greater thickness.
hand of an operator while the short leg of the
- tion.
In Figs. 5 .and 6 I have illustrated a modi?ed
form .of clamp embodying my invention as com
bellcrank extends substantially at right angles to
the handle portion so that when the clamping bar
prising‘ a pair of supports 2| and 22 which, like
1 is in its clamping or working position, as shown
the supports l and 2, may be provided with hori
in Fig. 1, a line extending through the axes of 20 zontally extending feet 23 adapting the supports
the pivot pins or rivets I I and I3 and the bolt
to be secured to a work table or working surface.
l4'will be a straight line, the short leg of the
In this form of hold-down device the clamping
bellcrank and the link l2 constituting in effect
bar 24 is pivotally mounted as by a pivot pin or
a toggle.
rivet 25 to the vertically extending portions of
To facilitate manufacture and assembly of the 25 the supports 2| and 22 to swing from a clamping
type of hold-down device illustrated in Figs. 1
or working position, as shown in full lines in
through 4, the short leg of the bellcrank consti
Fig. 5, to a released or non-working position, as
tuting the handle l0 may be slotted or bifurcated,
shown in dotted lines in Fig. 5.
as shown in Figs; 1 and 2, so that the link I2 may , r ' The clamping bar 24 is moved between these
be made of a thickness considerably less than the 30 positions by means of a handle 26 having its
thickness of the handle member ID and may be
lower end slotted as indicated at 21 to straddle
interposed in the slot formed'by bifurcating the
the rearward portion of the clamping bar 24 to
which it is pivoted by means of a pivot pin or
With the clamp structure as'thus far described,
rivet 28. The handle 26 is coupled to the sup
it will be apparent that moving the handle to a
ports 2| and 22 by means of a pair of links 29
substantially horizontal position, as is shown in
and 39 which may extend one on each side of the
Fig. 1, will cause the clamping bar to rotate about
handle 26 to which the links are pivotally con
its pivot pin 8 until the clamping bar is disposed
nected by means of a pivot pin or rivet 3|. The
in a substantially horizontal position as shown in I
lower ‘end of the links 29 and 30 engage crank
Fig. 1 and in this position the toggleformed by 40 pins 32 and 33 formed upon opposite ends of
the handle and link will be “straightened out”
a pin or section of rod 34, the crank pins being
and will act to lock the clamping bar ‘I in its
disposed eccentrically with respect to the axis
clamping or working position. In this position
of the pin 34. The pin 34 is rotatably mounted
the handle is substantially horizontal and lies
in circular openings in the supports 2] and 22
below the upper limits of the support members I 45 so that the pin 34 may be rotated relative to
and 2, thus being out of any possible obstructing
the supports. .
‘position. Likewise ‘movement of the handle in
_With the construction thus far described,
from the position shown in Fig. 1 to the position
movement of the handle 26 in a counterclock
shown in Fig. 4 will swing the clamping bar 1 ; . wise direction will swing the clamping bar 24 to
about its pivot 8 until the bar is disposed in, a 50 its working position, as illustrated in full lines
substantially vertical position, as shown in Fig. 4,
in Fig. 5, at which time the pivots 3|, 28 and
and in this position both the handle and the
33 will be disposed in a straight line, the com
clamping bar are disposed in positions which will
bination constituting a toggle joint in which the
not obscure the surface of the work table and will
toggle is "straightened out.” Movement of the
leave the work table accessible to the workman
_andle 26 in a clockwise direction will ?rst
for the placing of a new workpiece or the removal
‘break” the toggle and then will cause the clamp
of a ?nished piece,
_ing bar 24 to be moved in a clockwise direction
It will be observed that the slots IS in the sup
to its released or non-working position, as shown
ports I and 2 areformed on the arc of a circle
in dotted lines in Fig. 5.
and the shape of the slots is so disposed upon 60 The space between the outer end of the clamp
the supports that one end of the slot is consider
ing bar 24 and the‘ surface of the work table
ably higher from the work table than is the other
may be readily adjusted by rotating the pin 34
end of the slot. Thus if thelbolt I 4 is shifted
in its openings 35 to move the crank pins 33 to
from the position shown in Figs. 1, 2 and 4, and
a position closer to or further away from the
. is disposed in some other position within the slot, 65 work table surface. Any movement of the crank
the working position of the clamping bar ‘I will
pins 33 further toward the Work table surface
not be horizontal but will form a greater or lesser
will cause the'working position assumed by the
angle relative to the work table surface. Thus
clamping bar 24 to be with its outer end closer
by loosening the nut IS on the bolt and shifting
to the work table surface, such as is indicated in
the bolt rearwardly of the slot 15, the working 70 dash lines 36 in Fig. 5.
It will be apparent therefore that the _pin 34
position of the outer end of the clamping bar ‘I
may be rotated until the working position of the
may be disposed closer to the work surface, as
clamping bar 24 assumes any desired position
shown in the dash line position at I‘! in Fig. 2, to
adapted for the particular thickness of the work
accommodate the hold-down device for engaging
and holding a thinner or narrower workpiece than 75 piece with which it is to be associated. The pin
handle.
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55
a
2,408,586
may then be ?xed against inadvertent move
ment to some other position as by means of
welding the ends of the pin 34 to the supports
2| and 22.
It will therefore be observed that I have pro
vided a clamp or hold-down device which may
a support member adapted to rest upon the
_ working surface, a clamping bar; means pivoting
said clamping bar upon said support member
[for movement between a Working position dis
posing the end of the bar a predetermined dis
tance above the working surface to engage and
clamp a workpiece against the working surface
be readily adjusted to ?t a particular thickness
and a non-working position disposing the end
of workpiece and once 50 adjusted the adjust
of said bar at a greater distance from said sur
ment may be maintained either temporarily, as
face; a handle member for moving said bar
by the bolt and nut construction shown in Figs. 10 between said two positions; means pivotally in
1 through 4, or the adjusted position may be per
terconnecting said handle with said bar; and
manently ?xed, as indicated in Figs. 5 and 6.
means pivotally connecting said handle to said
In either case the manufacture of clamps or hold_
support including a pivot member engageable
down devices is facilitated, a single design of
with said support, a slot in said support for re
which may be manufactured in large quantities 15 ceiving ‘said pivot member, saidslot extending at
and then ?tted to di?erent distances between
an acute angle relative to the working surface
the work table and the clamping bar by merely
whereby positioning of said pivot member at
?xing the position of the adjusting device.
different positions along said slot will ?x the
While I have shown and described the preferred
working position of the end of said bar at dif
embodiment of my invention, I do not desire 20 ferent predetermined'distances above said work
to be limited to any of the details of construc
ing surface to thereby accommodate workpieces
tion shown and described herein, except as de
of different thicknesses, and means for locking
said pivot means in any position along said slot.
?ned in the appended claim.
I claim:
In a hold-down device for securing a work
piece to a working surface, the combination of:
25'
LOUIS A. SPIEVAK.
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