U.S. patent number 3,636,997 [Application Number 05/050,456] was granted by the patent office on 1972-01-25 for hacksaw frame.
This patent grant is currently assigned to Malco Products, Inc.. Invention is credited to Mark W. Keymer.
United States Patent |
3,636,997 |
Keymer |
January 25, 1972 |
HACKSAW FRAME
Abstract
A hacksaw frame with a frame arm telescopically adjustable
within a socket in a handle assembly, the frame arm being locked in
operating position within the socket and a blade simultaneously
tensioned by a movable lever on the handle assembly. Moving the
lever from an open to a locked position cocks and binds the frame
arm within the socket thereby rigidly securing the hacksaw frame in
operating position. The purpose of the foregoing abstract is to
enable the Patent Office and the public generally, and especially
the scientists, engineers, or practitioners in the art who are not
familiar with patent or legal terms of phraseology, to determine
quickly from a cursory inspection the nature and essence of the
technical disclosure of the application. The abstract is neither
intended to define the invention of the application, which is
measured by claims, nor is it intended to be limiting as to the
scope of the invention in any way.
Inventors: |
Keymer; Mark W. (Hopkins,
MN) |
Assignee: |
Malco Products, Inc.
(Minneapolis, MN)
|
Family
ID: |
21965356 |
Appl.
No.: |
05/050,456 |
Filed: |
June 29, 1970 |
Current U.S.
Class: |
30/513 |
Current CPC
Class: |
B23D
51/125 (20130101) |
Current International
Class: |
B23D
51/12 (20060101); B23D 51/00 (20060101); B27b
021/06 () |
Field of
Search: |
;145/33R,33A,34R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
970,770 |
|
Jun 1950 |
|
FR |
|
1,265,901 |
|
May 1961 |
|
FR |
|
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Koczo, Jr.; Michael
Claims
I claim:
1. A hacksaw for a blade comprising:
a frame including a forwardly extending frame arm and also
including a rearwardly disposed handle connected to the arm,
means on the forward end of the frame arm for connection to a
blade,
the frame having an elongate guide passage adjacent the handle and
extending in a fore and aft direction toward said means, the guide
passage having a noncircular transverse configuration,
an adjustable connector in said guide passage and including a blade
mounting slide having the transverse cross section of the guide
passage and having attachment means for connection to the blade,
the slide projecting forwardly out of the guide passage, and being
longitudinally slidable without rotation in the passage, the
adjustable connector also including an operating slide in spaced
relation with the blade mounting slide, and the connector also
including a screw on one of the slides and threaded into the other
of the slides for varying the spacing between the slides, and
a swingable linkage pivoted on the frame adjacent to the rear end
of the guide passage and including a swinging link connected to the
operating slide of the connector for producing fore and aft sliding
thereof in the guide passage, said linkage being swingable toward
and into locked position to move the operating slide rearwardly in
the guide passage to a preset blade tensioning position, and said
linkage also being alternately swingable away from said locked
position and to a release position to move the operating slide
forwardly in the guide passage to release tension on the blade and
permit removal thereof and to move the blade mounting slide endwise
out of the guideway to permit rotation thereof relative to the
operating slide to effect adjustment along the screw and thereby
accommodate variation in blade lengths.
2. The hacksaw according to claim 1 and said linkage including a
link with a connection to the operating slide and also including a
lever with connections to the frame and to said link, the
connections being pivots swinging over center through a plane
common to all pivot axes to the locked position wherein tension
through the slides holds the linkage in locked position.
3. The hacksaw according to claim 2 wherein the frame arm is
tubular and has a straight portion with an open rear end adjacent
to the handle to receive and confine a spare blade therein, the
lever of the linkage having a cover portion overlying the open rear
end of the tubular frame arm and being held thereagainst by the
tension on the blade acting through the slides and to hold the
pivots in over center position.
Description
BACKGROUND OF THE INVENTION
My invention comprises an improved hacksaw frame on which the
required adjustments for inserting and replacing blades can be
easily and rapidly made.
All hacksaw frames have the common purpose of providing a mounting
frame for a blade. Once the blade is properly mounted, all hacksaws
operate essentially the same regardless of differences in the frame
construction. The effectiveness of a hacksaw frame is determined by
the effort required to adjust the frame to blades of different
lengths and the ease with which worn blades can be replaced.
An effective hacksaw frame requires an adjustable frame arm for
blades of different lengths. Frame arms of most hacksaws are
inconvenient and cumbersome to adjust. Often the arms adjust by
sliding along and pivotally interlocking with a channel extending
from the handle; the frame arm may carry a series of spaced
transverse slots which are engageable with a stop on the channel to
lock the frame arm in the channel. Frame arm length is adjusted by
pivoting the frame arm at an angle to the channel to disengage the
stop from the slot and then sliding the arm along the channel until
the stop engages a new slot which locks the arm at the desired
length. Unfortunately, this construction permitted the frame arm
slot to easily disengage the stop and slip to an unwanted position
if the hacksaw was bumped before the blade was tensioned. It was
often necessary for an operator to hold the frame arm in proper
position with one hand until the blade was inserted and tensioned.
This was inconvenient because of the difficulty of inserting and
tensioning a blade using only the remaining hand. My invention
permits an operator to simultaneously lock the frame arm in
position and tension the blade with a single, rapid, lever
movement.
Another important consideration in hacksaw frame design is the ease
with which blades can be removed and replaced when worn or broken.
This seemingly simple operation is frequently time consuming and
awkward with many hacksaw frames. Frequently when blade tension was
released and the blade removed, the frame arm disengaged its stop
and shifted to a new position thus requiring readjustment and
relocking before a new blade could be inserted. Since it is
frequently necessary to replace worn blades it is desireable that a
hacksaw frame be designed for rapid removal and replacement of worn
blades.
Few hacksaw frames include all the features necessary for rapid,
easy adjustment of the frame arm length and quick replacement of
worn blades while incorporating a compact, streamlined overall
design. My invention substantially diminishes the problems
described and is simple and fast to operate.
SUMMARY OF THE INVENTION
My invention comprises an improved hacksaw frame having a frame arm
which telescopes into and out of a socket in the handle assembly. A
blade can be quickly inserted in my frame and the frame arm easily
and rapidly adjusted to proper length. A lever assembly mounted on
the handle assembly cocks and binds the frame arm in the socket and
simultaneously tensions the blade when a lever is moved from an
open to a locked position.
If desired, detents can be installed on the frame arm and socket to
indicate appropriate frame arm positions for blades of known
lengths. My detent device retains the frame arm in proper position
while blades are changed and eliminates the frame arm readjustments
commonly required with most hacksaw frames.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view, partly in section, of a hacksaw frame
embodying my invention.
FIG. 2 is an exploded view of the handle assembly of the frame of
FIG. 1.
FIG. 3 is a sectional side view taken through the lower end of the
handle assembly of FIG. 1.
FIG. 4 is a cross-sectional view of the handle assembly of FIG. 1
taken along cutting plane 4--4 showing my detent device and blade
storage compartment.
FIG. 5 is a pictorial view of a handle assembly illustrating a
modification of my invention.
DESCRIPTION AND OPERATION OF THE PREFERRED EMBODIMENTS
My hacksaw frame invention, shown generally at 10 in FIG. 1, has a
frame arm 12 and a handle assembly 14 containing a socket 16.
The frame arm 12 has its rearward end 18 slideably mounted in close
fitting relationship with the socket 16 for movement in the
directions indicated by arrows 20 to adjust the frame length for
blades of different length. Frame arm 12 includes a blade mounting
plug 22 at the forward end 24 of the arm.
A standard hacksaw blade 26 is held to the forward end 24 of arm 12
by a peg 28 on mounting plug 22. The other end of the blade 26 is
held by mounting peg 30 on blade mounting block or slide 32 which
is a part of the adjustable connector. A second pair of mounting
pegs 34 and 35 permit a blade to be mounted perpendicular to the
blade position illustrated.
The handle assembly 14 has handle grips 36 and is provided with a
guard 38 for protection of the operator. The handle assembly may be
formed from a variety of rigid materials such as steel or
aluminum.
Referring now to FIGS. 2 and 3, lever assembly or locking linkage
42 has the blade mounting block 32 with a screw 43 which engages
threaded bore 44 (FIG. 3) in operating slide 46 which is also a
part of the adjustable connector. Blade mounting block 32 and slide
46 collectively provide an adjustable connector for the lever
assembly 42.
A lever 48 is pivotally joined to connector 46 through a linkage 50
by pins 51 and 52. The lever assembly 42 is here shown as including
mounting block 32, connector 46, linkage 50, lever 48, and pins 51
and 52. The lever assembly 42 is slideably carried within a guide
passage 54 (FIG. 3) at the base of the handle assembly 14. The
lever assembly 42 is retained in the passage by pivot screw 56
(FIG. 1-3) which passes through bores 57 and 58 of the handle
assembly and lever respectively, and is threaded to the handle
assembly.
When lever 48 is moved from open position 39 (FIG. 1) to a locked
position in recessed slot 60 (FIG. 3) the blade mounting block 32
moves along passage 54 a set distance. When in a locked position
pin 52 is in an over-dead-center relationship relative to the line
joining pin 51 to screw 56. The movement along guide passage 54 is
ample to tension the blade 26 and cock and bind the frame arm 12 in
socket 16 as will now be described.
The blade 26 is inserted and tensioned and frame arm 12 cocked in
socket 16 by first placing the lever 48 in open position as shown
at 39 (FIG. 1) and sliding the frame arm 12 to a position in socket
16 which spaces the mounting pegs 28 and 30 appropriately for the
given blade. The blade is then inserted and the lever 48 moved to
locked position in slot 60 (FIG. 3). This lever movement causes the
blade mounting block 32 to slide rearwardly along guide passage 54
and exert a tensioning force on the blade 26 and an equal force on
forward end 24 of frame arm 12. This force cocks arm 12 in socket
16 and binds the arm against the sides of socket 16 at 62 and 64
(FIG. 1) to thereby lock the arm firmly in the socket. The hacksaw
is now ready for use.
The ease with which different size blades can be inserted in my
frame can be increased by equipping my frame arm 12 and socket 16
with cooperating detent means. In FIG. 1 the frame arm 12 is shown
with a spring-loaded detent device 66. The detent device 66 (FIG.
4) extends completely through the frame arm 12 and snaps into
cooperating detent apertures 68 and 68a in the handle assembly. Two
or more pairs of such apertures can be provided; FIGS. 1 and 2 show
a first pair at 68 and a second pair at 70. To adjust the length of
the frame arm 12 extending from socket 16, the arm is slid along
socket 16 until the detent device 66 snaps into cooperating detent
apertures at 68 or 70. When the detent device 66 engages one of
these pairs of apertures the frame arm is the appropriate length
for the particular blade. Even if the lever 48 is moved repeatedly
or the frame jarred, the arm position remains constant thus
increasing the ease of inserting and removing blades.
When a different size blade is to be inserted, the lever 48 is
moved to open position, the old blade removed, the detent device 66
pushed inwardly at both of the apertures 68 and 68a (FIG. 4) and
the arm 12 slid along socket 16 until the detent device 66 engages
the next pair of apertures 70 (FIG. 1). This arm adjustment can be
performed quickly and easily and once adjusted the detent device 66
keeps the arm in the desired position even when the saw is jarred
or bumped. It should be understood that the detent device 66 is not
needed to lock the arm 12 in the socket 16 so as to produce a rigid
frame for cutting; the arm is locked in the socket by the cocking
and binding action already described. The purpose of detent device
66 is to aid an operator in properly positioning the arm for
conventional blades and to prevent the arm from slipping along or
out of the socket 16 when a blade is being replaced.
It is helpful to form guide passage 54 with a square cross section
to prevent the mounting block 32 from accidentally rotating and
changing its adjustment when lever assembly 42 is in position in
passage 54 with pivot screw 56 in place. Because of this
construction the adjustable connector of the lever assembly 42
seldom requires adjusting when blades are removed or inserted.
When necessary to vary the length of lever assembly 42 in order to
accommodate various commercial blades to the frame arm positions
established by my detents, pivot screw 56 (FIG. 2) is removed and
lever assembly 42 (FIG. 3) slid forwardly along passage 54 until
mounting block 32 is outside passage 54. Mounting block 32 is
rotated to advance or retract screw 43 in bore 44 thereby changing
the length of the lever assembly, which can then be remounted in
passage 54. The screw 56 may be formed with a knurled head for ease
of removal.
Referring now to FIG. 4, frame arm 12 can be made from a tubular
rod having a hollow interior 72. One or more extra blades can be
stored within the interior 72 of the frame arm for use in the event
the installed blade 26 becomes unusable. They can be inserted or
removed from the interior 72 of the arm 12 by removing the arm from
socket 16.
A modification of my handle assembly shown in FIG. 5 permits an
operator to gain access to the blade storage compartment from the
rear of the handle assembly 76. The lever 78 has a cap 80 designed
to block an opening 82 at the upper rear side of the handle
assembly. When the lever 78 is moved to an open position, an
operator can insert or remove one or more extra blades. When the
lever 78 is in locked position, retaining means shown at 84 engage
the opening 82 and hold the lever 78 in locked position.
While I have described a preferred embodiment of the present
invention, it should be understood that various changes,
adaptations, and modifications may be made therein without
departing from the spirit of the invention and the scope of the
appended claims.
* * * * *