US2919912A

US2919912A - Workpiece holding clip

Info

Publication number: US2919912A
Application number: US698554A
Authority: US
Inventors: Matthew E Brinkhaus
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-11-25
Filing date: 1957-11-25
Publication date: 1960-01-05
Anticipated expiration: 1977-01-05

Description

M. E. BRINKHAUS WORKPIECE HOLDING CLIP Filed Nov. 25, 1957 Jan. 5

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United States Patent WORKPIECE HOLDING CLIP Matthew E. Brinkhaus, Fresno, Calif.

Application November 25, 1957, Serial No. 698,554

3 Claims. 01. 269-415) The present invention relates to a workpiece holding clip particularly adapted to hold preformed edges of a pair of sheet members in predetermined association preparatory to and while interconnecting such edges.

The utility of the subject invention is conveniently de scribed in connection with the formation of a sheet metal pipe or duct which is widely used in the installation of heating and ventilating systems. Such a duct is usually made from a flat piece of sheet metal bent along lines longitudinally thereof to provide bottom, side and top walls in rectangular relation to each other. Three of the corners of the duct are integral but the fourth corner consists of a pair of adjacent edges which must be interconnected in air-tight, relatively rigid and dependable relation.

The conventional manner for seaming the corner of a duct of this nature is by utilization of the Pittsburg seam or joint. In order to provide the Pittsburg joint, one of the walls, a side wall for example, is reversely bent downwardly along a first break line and then again reversely bent upwardly, in simulation of a 2, along a second break line to provide an elongated pocket extended longitudinally of the duct. Theouter reversely bent flange usually extends above the first break line a distance substantially equal to the distance between the first and second break lines. The top wall is bent along a longitudinal line adjacent to its edge to provide a marginal male flange adapted to be received into the pocket of the side wall. After being interfitted in this manner, the extended portion of the outer flange of the side wall is bent over the adjacent edge of the top wall whereby the edges of the walls are interconnected.

It is found that while one end of the outer flange along the length of a duct is being bent over against the top wall of the duct, usually by hammering, the opposite end of the male flange frequently vibrates uncontrollably in the pocket thereby tending to dislodge the male flange from the pocket throughout the length thereof. In order to obtain a substantially air-tight, dependable connection, it is necessary that the male flange be held snugly in the pocket while the entire length of the outer flange is being hammered over. If this relationship does not exist, the male flange is loosely held in the pocket, the joint is not sufliciently air-tight, and the duct walls are permitted to shift both transversely and longitudinally with respect to each other.

Accordingly, it is an object of the present invention to provide a workpiece holding member adapted to hold preformed edges of a pair of sheet members in predetermined association preparatory to and while interconnecting such edges.

Another object is to facilitate the edgeward connection of apair of sheet members.

Another object is to facilitate interconnection of sheet members adapted to be joined through the utilization of a Pittsburg joint or seam.

' Other objects are to provide a device of the nature described which is simple and economical to construct of the subject invention mounted in predetermined holding positions along said corner of the duct.

Fig. 2 is a somewhat enlarged end view of the duct and a holding clip of Fig. 1 showing the adjacent wall:

of the corner of the duct preliminary to being joined.

Fig. 3 is a fragmentary somewhat enlarged perspective view of the adjacent walls of the corner of the duct prior to being joined and a perspective view of one of the holding clips attached to the walls.

Fig. 4 is a fragmentary view of the adjacent Walls of the duct after being interconnected by the Pittsburg joint as facilitated by the utilization of the holding clips of the present invention.

Referring more particularly to the accompanying drawing, an elongated sheet metal duct is generally indicated by the numeral 10. The duct provides an elongated bottom wall 11, integrally upwardly extended

side walls

12 and 13 perpendicular to the bottom wall, and a substantially horizontal top wall 14 integral with one of the side walls in spaced parallel relation to the bottom wall.

The duct 10 is formed from a single piece of sheet metal by bending the metal along break lines constituting thecorners between adjacent side, bottom and top walls. In order to complete the duct, the top wall 14 must be connected to the side wall 13 and for this purpose a Pittsburg seam or joint 20, as best illustrated in Fig.4, is employed. In order to form this joint, the top wall of the duct provides a downwardly extended male flange 22 in right-angular relation to a horizontal inner section 23 thereof. For purposes of subsequent reference, a longitudinally extended, right-angularly bent edge 24 is defined between the inner section and the male flange of the top wall, and the male flange terminates in a lower edge 25.

Further, the Pittsburg joint 20, insofar as the side wall 13 is concerned, includes an inner wall portion 28 which issubstantially vertical, an intermediate flange 29 integral with the inner portion and reversely downwardly return bent relative thereto, and an outer flange 30 integral with the intermediate flange reversely upwardly return bent relative thereto and terminating in an upper longitudinal edge 31 spaced above a break line 32 be-' relation with the inner setcion 23 when the male flange IS in the pocket, as described.

. A workpiece holding clip 40, as provided by the present invention, includes an elongated intermediate J-shaped plate 42 having an elongated shank portion 43 and a lower return bent lip 44 defining a channel 45 adapted slidably to receive the male flange 22 of said inner sectionf 23 therein. The clip also provides an inner L-shaped plate 43 including a mounting wing 49 secured, as by welding, to the shank 43 of the intermediate plate 42 in longitudinally spaced relation to the 'lip 44 and a guiding wing 50 perpendicularly laterally outwardly extended from the shank and spaced above the base of the pocket 35 a distance substantially equal to the length of the male flange 22 so as to overlay the inner section when the male flange is fitted in the pocket.

Still further, the clip has an elongated outer stepped plate 55 including an upper segment 56 secured, as by welding, to the shank 43 of the intermediate plate 42 on the opposite side thereof from the inner plate 48, an intermediate oifset segment 57 integral with the upper segment and laterally outwardly extended from the shank 43 at a position below the guiding win 50, and a lower segment 58 integrally extended from the offset segment in substantially parallel relation to the upper segment and defining a slot 59 with the shank 43 of the intermediate plate 42.

Operation The operation of the described embodiment of the subject invention is believed to be readily apparent and is briefly summarized at this point. The duct is initially formed to provide the bottom, side and

top walls

11, 12, 13 and 14, and the bends for the Pittsburg joint 2% in the top and side walls are provided preparatory to interconnection of the side and top walls in the manner above described and which is well-known in the art.

Thereupon, a plurality of the workpiece holding clips 40 are edgewardly attached to the side and

top walls

13 and 14 in longitudinally spaced relation therealong in the following manner. The shank 43 of the clip is interposed between the male flange 22 and the outer flange 30 in upright position and in substantially parallel relation to the inner portion 28 of the side wall. The male flange is downwardly fitted into the upwardly disposed pocket 35 so that the guide wing 50 overlaps the inner section 23 of the top Wall. Thus attached, the clip is longitudinally slidably fitted on the top wall of the duct. The downwardly disposed slot 59 is then longitudinally slidably fitted downwardly over the upwardly extended outer flange 30. The upper edge 31 slidably engages the oflset segment 57 of the outer plate 55 limiting relative movement of the side and top walls toward each other. In this connection the lower end 44 of the intermediate plate 42 is slidably engaged with the upper break 32 of the side wall at the mouth of the pocket 35 and is sufficiently larger than the pocket to preclude movement of the intermediate plate downwardly into the pocket. This, of course, also prevents movement of the male flange downwardly into the pocket.

A series of the clips 40 are attached to side and

top Walls

13 and 14 of the duct in the above described manner and are located along the duct from the end where the joint is initially to be formed. Accordingly, at one end of the duct from which the nearest clip is spaced, the male flange 22 is inserted into the pocket 35, and the clamping portion 36 of the outer flange 30 is hammered downwardly along a break line 60 into overlaying engagement with the inner section 23 of the top wall 14. During such hammering, the workpiece holding clips 44) urge the end of the male flange downwardly toward the pocket 35. The Weight of these members causes the lower ends of the J-shaped plates 42 to press against the mouth of the pocket 35 so that the tendency of the male flange to jump out of the pocket or otherwise to move vertically is minimized. In addition, the group of clips precludes lateral movement of the male flange with respect to the outer flange 30 which is held between the intermediate and

outer plates

42 and 55 of the clips. It is to be observed, however, as best illustrated in Fig. 1, that the inner section 23 of the top wall 14 and the clamping portion 36 of the outer flange 30 have a slightly upward curvature between the portions of the inner section and outer flange which have been hammered into contact and those portions of the inner section and outer flange which have not as yet been so hammered. The parts of the outer flange which are bent over against the top wall 14 of the duct 1% urges the male flange 22 even more snugly into the pocket and thus urges the lower end of the intermediate plate 42 more snugly against the mouth of the pocket.

As the outer flange 30 is hammered over against the outer section 23 progressively longitudinally of the duct it), the holding clips 40 are successively longitudinally slidably moved along the

edges

25 and 31 of the

walls

13 and 14. Eventually all of the clips are collected in sideby-side relation at the end of the duct and are then removed one by one frorn such end to complete bending over of the outerflange. In this manner the Pittsburg seam 20 is formed in a more dependable, substantially airtight, and compact association. It is found by using the holding members of the subject invention, the tendency of the male flange 22 to move laterally and/ or elevationally with respect to the pocket 35 is minimized with the result that a vastly superior joint is achieved. Although the duct has been described as being in a horizontal position and the Pittsburg joint and the clip as having a certain orientation, these positions are not to be regarded as limiting but merely as exemplifying the preferred utilization of the invention. The utilization of the described clips not only facilitates the dependable formation of the described seams but enables a sole workman to achieve the formation unassisted by other workmen normally required to hold the seam in assembled condition during completion.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A tool for aligning a Pittsburgh joint in advance of forming said joint between first and second angularly related Walls of substantially uniform thickness wherein said first wall provides a male flange angularly related to an inner section and wherein the second wall provides a substantially U-shaped pocket in opposed relation to and adapted to receive the male flange and defined by relatively inner and outer flanges, the outer flange being longer than the inner flange, said tool comprising an intermediate J-shaped plate having an elongated shank portion adapted to be slidably positioned between the male and outer flanges, a lip integrally return bent with respect to and in closely adjacent spaced relation to the shank portion providing a channel adapted slidably to receive the male flange, the return bend between the lip and the shank portion providing an endwardly tapered wedge-shaped end on the J-shaped plate, said wedgeshaped end having a width greater than the Width of the pocket and being adapted to fit against the relatively inner and outer flanges at the entrance to the pocket for holding the male flange in substantially the same plane as the pocket but preventing the male flange from entering the pocket; a guide member rigidly connected to the shank portion in longitudinally spaced relation to the lip and laterally extended from the shank portion in opposed relation to the channel for slidably overlaying the inner section of said first wall thereby to hold the male flange in the channel; and an outer plate segment Connected to the shank portion on the opposite side thereof from the guide member and extended longitudinally of the shank portion in spaced substantially parallel relation thereto on the opposite side of the shank portion from the lip to provide a slot with the shank portion slidably adapted to receive the outer flange of the second wall, the

a slot and the channel having minimum widths substantially equal to each other and to the thickness of the walls.

2. The tool of claim 1 wherein the distance between the wedge-shaped end of the J-shaped plate and the point of connection of the outer segment plate to the shank I portion is substantially equal to the diiference between the lengths of said relatively inner and outer flanges whereby relative movement of the male flange and the pocket toward each other is limited by bottoming of the male and outer flanges in the channel and slot, respectively.

3. For use in forming a Pittsburg joint in a corner of a sheet metal duct including first and second substantially perpendicular walls of substantially the same thickness terminating in edges to be connected in overlapping relation, said first wall having an inner section and a male flange substantially perpendicularly integrally extended from the inner section, said second wall having an inner wall portion, an intermediate flange integrally return bent with respect to and in contact with the inner wall portion, and an outer flange integrally return bent with respect, and in spaced substantially parallel relation, to the intermediate flange to provide a female pocket adapted to receive the male flange, the outer flange being extended endwardly beyond the return bend between the inner wall portion and the intermediate flange to the terminating edge of said second wall and being adapted to be folded over against the inner section of the first wall when the male flange is in the pocket; 2. clip for holding the male and outer flanges in juxtaposed relation with the male flange in the plane of the pocket but in advance of fitting the male flange in said pocket comprising an intermediate J-shaped plate having an elongated flat shank portion longitudinally slidably positionable between the male flange of the first wall and the outer flange of the second wall wherein said male and outer flanges are on opposite sides of the shank portion and the male flange is out of the pocket, a lip integrally return bent with respect to and in spaced relation with the shank portion to provide a V-shaped channel having a minimum width substantially equal to said thickness of the walls and slidably adapted to receive the male flange, the return bend between the lip and the shank portion being adapted to fit between the intermediate and outer flanges at the entrance to said pocket thereby to prevent the male flange from entering the pocket; an inner L-shaped plate having a mounting wing secured to the shank portion of the J -shaped plate in longitudinally spaced relation to the lip and a guiding wing laterally outwardly extended in substantially perpendicular relation from the shank portion in longitudinally spaced opposed relation to the channel so as slidably to overlay the inner section of said first wall thereby to hold the male flange in the channel; and an outer stepped plate including a first end segment secured to the shank portion on the opposite side thereof from said mounting wing, an ofiset segment integrally laterally outwardly extended from the upper segment at a position longitudinally of the shank portion substantially opposite to the position from which the guiding wing extends, and a second end segment integrally endwardly extended from the oflset segment in spaced substantially parallel relation to the shank portion thereby providing a slot beween the shank portion and the second end segment, said slot having a width substantially equal to said thickness of the walls and being slidably adapted to receive the outer flange of the second wall whereby the male flange of the first wall is held in substantially the plane of the pocket and to the outer flange of the second wall in advance of fitting the male flange in the pocket and of folding the outer flange against the outer section of the first wall.

I References Cited in the file of this patent UNITED STATES PATENTS 1,409,100 Hamer Mar. 7, 1922 2,200,047 Tinnerman May 7, 1940