US3826483A

US3826483A - Planar work holder

Info

Publication number: US3826483A
Application number: US00286424A
Authority: US
Inventors: W Siegel
Original assignee: W Siegel
Current assignee: Pace Inc
Priority date: 1972-09-05
Filing date: 1972-09-05
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30

Abstract

A planar work holder supported only from the rear by a support bar with the work piece being retained between a cross bar and two forwardly extending arms. A tension bar is adjacent one arm secured thereto by pins in a way which allows the tension bar limited movement toward or away from the arm. Springs and a multiple position detent cooperate to lock tension bar close to arm so that a work piece can be placed between the tension bar and arm. Release of the detent to a second position permits the springs to bias tension bar away from arm so as to grip the work piece between arm and tension bar with the force exerted by the springs.

Description

United States Patent 1 Siege] [11] 3,826,483 [451 July 30, 1974 1 1 PLANAR WORK HOLDER [21] Appl. No.: 286,424

Primary Examiner-Roy Lake Assistant ExaminerNei1 Abrams Attorney, Agent, or Firm-Fidelman, Wolffe, Leitner & Hiney [57] ABSTRACT A planar work holder supported only from the rear by a support bar with the work piece being retained between a cross bar and two forwardly extending arms. A tension bar is adjacent one arm secured thereto by pins in a way which allows the tension bar limited movement toward or away from the arm. Springs and a multiple position detent cooperate to lock tension bar close to arm so that a work piece can be placed between the tension bar and arm. Release of the detent to a second position permits the springs to bias tension bar away from arm so as to grip the work piece between arm and tension bar with the force exerted by the springs.

5 Claims, 7 Drawing Figures PAIENTED 3.828.483

sum 1 11$ 2 1 PLANAR WORK HOLDER This invention relates to a work handling and positioning holder and particularly to a holder adapted to support and retain articles like circuit boards so that assembly work or repair work may be efficiently conducted thereon.

Repair and maintenance of electronic equipment sometimes requires that the mechanic or technician do fine work on components of an individual circuit board e.g., patch a broken lead, replace a component, etc. To do so, the technician must have a fixture in which the circuit board can be mounted securely and leave both hands of the technician free to perform the necessary operations. Desirably the work holding fixture should be constructed so that it supports with substantial stability. Rocking of the work piece should be avoided. The holder should in no way obstruct the technicians access to any part of the board. Also, the holder should be constructed so that illumination may be provided and a magnifying glass may be positioned above, over the work piece (electronic circuitry gets smaller and smaller).

Other desirable features for a work handling and positioning holder are an easy insertability therein of the circuit board and an ability to rotate the circuit board through 180, preferably 360. In addition, a capability for adjustment in size is desirable for repair needs. A broad range of circuit board sizes will be seen by the repair technician.

The structure of the present work holding fixture contains all of the above noted features.

For further understanding of the present invention, reference is now made tothe attached drawings wherein:

FIG. 1 is a perspective view of the holder of the present invention;

FIG. 2 is a front elevational view of the holder; FIG. 3 is a plan view of the holder;

FIG. 4 is a side section taken along line 8-4 of FIG. 3;

FIG. 5 is a side elevational view of the holder, from the right side thereof;

FIG. 6 isa side sectional view taken along lines 66 of FIG. 3; and

FIG. 7 is a side sectional view taken along lines 7-7 of FIG. 3.

Referring now to the drawings, and particularly to FIGS. 1 and 3, it may be seen that the work handling and positioning holder 10 ofthe present invention comprises a cross bar 12 attached to a support rod 16, a central work support 14 is secured to support rod 16, and cross bar 12 has an angular in cross-section. A square cross-section shape 18 is illustrated in the mode of the drawings.

On the left side thereof is a universal arm 20 and on the right side thereof is a tension arm assembly 22, both of which are slidably disposed on cross bar 12. The work piece 24 which, for example, may be a circuit board, seats in V-

shaped slots

30,32,34 provided for this purpose, respectively, on center support 14, on universal arm 20, and on the tension arm 42 forming part of the tension arm assembly 22.

As may be seen from the drawings, the initial size ad justment of holder 10 to the workpiece 24 is made by sliding universal arm 20 and tension arm assembly 22 along the length of cross bar 12, the base 39 of universal arm 20 having a square aperture not shown for that purpose (as does the base of universal arm 40) which forms part of tension arm assembly 22. Aperture 36 is shaped and sized to easily fit cross bar 12. The knob 38, which threads into base 39 of universal arm 20 at a corner of the aperture 36 and cross bar 12, acts like a take up and set screw to lock arm 20 in place on cross bar 12. Thus

universal arms

20 and 40 are positioned on cross bar 12 at approximately the proper spacing for the particular work piece 24 to be mounted on holder 10.

As has already been indicated, tension arm assembly 22 includes universal arm 40 and tension bar 42. They are secured together by a plurality of pins 44. The pins, which may be machine screws, are fixed to tension bar 42 but pass through oversized holes in universal arm 40, being thereby free to reciprocate relative to arm 40 within the limits set by the length of pins 40 and the inability of their stop members (e.g., the screw heads) to enter the holes in universal arm 40. Compression springs 46 on pins 44 bias tension bar 42 away from arm 40 as shown in FIG. 3. Other spring biasing means may, of course, be employed. A two position detent or cam 48 is associated with the center pin 45 to lock the tension arm assembly 22 in a spring compressed position when cross pin 52 rides to the upper level 54, one at each end of detent 48. The other position permitted by detent 48 is the extended or spring biased position which occurs when the cross pin 52 seats in the base of V-notch 56 at the center of detent 48. The pin is retained in the V-notch 56 by compression springs 46. Detent 48, which seats on and straddles the side of universal arm 40, as is shown in FIGS. 1 and 6, slides on the universal arm 40 and can be moved from the spring biased position with cross pin 52 seated at the base of V-notch 56 to the spring compressed position with pin 52 on the upper level 54 so as to retract tension bar 42 closer to arm 40.

Insertion of a work piece such as a circuit board into work holding fixture l0 involves spacing the universal arm 20 and the tension arm assembly 22 to nearly the spacing appropriate for the work piece with tension arm 22 set in retracted position; that is, with cross pin riding on plateau 54. The gap between the opposing edges of universal arm 20, tension bar 42 should be just enough to allow work piece 24 to fit easily therebetween. Then, while work piece 24 is retained against the

notches

34 and 30 in universal arm 20 and center support 14 with one hand, the other hand slides the detent 48 to center pin 52 which releases tension bar 42 to assume its spring biased position. This engages the notch 32 at the edge of tension bar 42 against the work piece and locks the work piece in place, biased there by springs 46. The work piece is now rigidly retained in fixture 10. The normal repair or assembly activities carried out on a work piece 24 do not involve sufficient lateral forces on springs 46 to unseat work piece 24.

The particular suitability of fixture 10 for electronic repair activities on circuit boards can now be appreciated. All supports, including notably universal arm 20 and tension arm assembly 22, constitute almost planar extensions of work piece 24. No projections nor forwardly extending members interfere with vision or movement. All operations are carried out on the work piece with ease. Support for fixture 10 is from the rear, thereby through center rod 16. The area immediately above the fixture and the work piece has been kept 3 clear. A magnifying glass can be disposed above work piece 24 and any desired optical lighting system can be set above or to the side of work piece without interferring with whatever operations are required on the work piece 24.

The angular e.g., square shape of cross bar 12 and of aperture 36 of universal arms and 40 allow a high degree of structural rigidity in their connection, which means that the work piece will not rock or otherwise move under the stresses applied thereto by the mechanic. The fixture hangs entirely on support rod 16, rotation through 360 can be accomplished simply by rotating fixture 10 on the axis of support rod 16.

A separate but significant advantage of the fixture 10 is that it may be'formed from relatively inexpensive, easy to manufacture components (like barstock for support rod 16 and cross bar 12), a stamping or molding for center support 14, commonly available hardware like machine screws (pins 44), knobs, etc. Desirably the

universal arms

20,40 are cast aluminum members but even there the

arms

20 and 40 are identical.

On occasion, a repair situation will arise wherein the normal placement of the workpiece 24 between the V-

slot edges

30, 32 and 34 are not adequate to the work intended thereon and a more rigid connection is re quired. For such purposes, a multiplicity of tapped holes 60 are provided in

arms

20 and 40 and in tension bar 42. Presence of these tapped holes permit a work piece to be attached through threaded members directly to the top of arm 20 and either arm 40 or tension bar 42 should such be necessary. Alternatively, the tapped holes 60 may be employed to mount secondary clamping devices for holding round connectors, chasses, etc. It should be noted that the tensionarm arrangement permits the fixture to securely grip work pieces having non-parallel side edges and assures uniform gripping pressure along the side edge length of the work piece e,g., circuit boards, etc.

What is claimed:

1. A work handling fixture of planar configuration 4 comprising:

a centrally supported cross bar with a rearwardly extending centrally mounted support member and two forwardly extending arms slidably mounted thereon and releasably lockable thereto;

a forwardly extending tension bar between said arms adjacent one of said arms and joined thereto by means which permit limited movement toward and away from said arm;

spring biasing means normally urging said tension bar away from said arm;

and a multiple position detent means coacting with said spring biasing means wherein one position of said detent locks said tension bar close to the adjacent arm, whereby a work piece may be placed between the tension bar and the opposing arm, said detent means having a second position that permits the spring biasing means to bias said tension bar away from the adjustment arm whereby a work piece disposed between the tension bar and the opposing arm will be gripped therebetween and retained by the spring force of the spring biasing means.

2. The fixture of claim 1 wherein a center support means is mounted on said cross bar whereby the rear edge of a work piece may be supported thereby.

3. The fixture of claim 1 wherein the work piece gripping edges of the one arm and tension bar have a longitudinally extending V-shaped slot formed therein whereby the work piece seats'in said slots, and thereby is gripped more securely.

4. The fixture of claim 1 wherein the arms are identical.

5. The fixture of claim 1 wherein saidcross bar is angular in cross section; wherein each arm is provided with a matching aperture therein for sliding on said cross bar; and wherein set screw means disposed at a corner of the angular cross section serves to wedge lock arm to cross bar releasably.

Claims

1. A work handling fixture of planar configuration comprising: a centrally supported cross bar with a rearwardly extending centrally mounted support member and two forwardly extending arms slidably mounted thereon and releasably lockable thereto; a forwardly extending tension bar between said arms adjacent one of said arms and joined thereto by means which permit limited movement toward and away from said arm; spring biasing means normally urging said tension bar away from said arm; and a multiple position detent means coacting with said spring biasing means wherein one position of said detent locks said tension bar close to the adjacent arm, whereby a work piece may be placed between the tension bar and the opposing arm, said detent means having a second position that permits the spring biasing means to bias said tension bar away from the adjustment arm whereby a work piece disposed between the tension bar and the opposing arm will be gripped therebetween and retained by the spring force of the spring biasing means.

3. The fixture of claim 1 wherein the work piece gripping edges of the one arm and tension bar have a longitudinally extending V-shaped slot formed therein whereby the work piece seats in said slots, and thereby is gripped more securely.

4. The fixture of claim 1 wherein the arms are identical.

5. The fixture of claim 1 wherein said cross bar is angular in cross section; wherein each arm is provided with a matching aperture therein for sliding on said cross bar; and wherein set screw means disposed at a corner of the angular cross section serves to wedge lock arm to cross bar releasably.