US2998289A

US2998289A - Feed mechanisms

Info

Publication number: US2998289A
Application number: US856601A
Authority: US
Inventors: Runciman Robert Davidson
Original assignee: General Electric Co PLC
Current assignee: General Electric Co PLC
Priority date: 1958-12-04
Filing date: 1959-12-01
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29
Also published as: GB913927A

Description

Aug. 29, 1961 R. D. RUNCIMAN FEED MECHANISMS 2 Sheets-Sheet 1 Filed Dec. l, 1959 O 7mm Aug. 29, 1961 R. D. RUNCIMAN FEED MECHANISMS 2 Sheets-Sheet 2 Filed Dec.

Il-FTQ KN SYS United States Patent O '2,998,289 FEED MECHANISMS Robert Davidson Runcim'an, Coventry, England, assignor to The General Electric Company Limited, Kingsway, London, England Filed Dec. f1, 1959, Ser. No. 856,601 Claims priority, application Great Britain Dec. 4, 1958 3 Claims. (Cl. 312-71) This invention relates to feed mechanisms.

According to the invention, a feed mechanism includes a container which is elongated and is open at both ends, the container being adapted to contain a plurality of similar articles abutting against one another in an orderly succession extending along the length of the container, a ram which is arranged to bear against an end one of the succession of articles, and a reciprocable member which in operation has, a substantially constant length of stroke and which is coupled to the ram by a linkage at least partly constituted by a ratchet and pawl mechanism, the arrangement being such that during each forward stroke of the reciprocable member the articles in the container are pushed lengthwise through the container by the ram overa distance substantially equal to the spacing of the articles in the container.

One arrangement in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view, shown partly broken away, of a mechanism for mounting valve holders on printed circuit panels;

FIGURE 2 is an enlarged central sectional elevation the upper part of the mechanism; and

FIGURE 3 is au enlarged central sectional elevation of the lower part of the mechanism.

The mounting mechanism is designed to form one of a number of component insertion heads of an in-line assembly machine such as is described in United States Patent No. 2,890,456. The in-line assembly machine includes a track along which are pushed a number of printed circuit panels each mounted on, and located in a fixed position with respect to, a supporting platen, and the component insertion heads are mounted at intervals along the length of the track. The platens are arranged to be moved along the track intermittently so that they are positioned in sequencebeneath the series of component insertion heads, the platens being located accurately in position while the heads operate to mount electrical components on the panels supported by the platens.

Referring to the drawings, the mechanism is adapted to mount valve holders 10 on to printed circuit panels such as the panel 12 (see FIGURE 3). Each valve holder 10 includes a substantially circular cylindrical ceramic block 14, the block 14 having a diameter of about 0.7 inch and a thickness off about 0.2 inch. A number of valve pin sockets 16 are formed in the block 14, and a corresponding number of similar metal tags 18 are respectively formed integral with the sockets 16. The tags 18 are disposed at intervals around the-block 14, and are `bent so that the end portions of the tags 18 project perpendicularly from one end face of the block 14, the end portions of the tags 18 being disposed slightly beyond the periphery of the block 14; the arrangement is such that a number of the holders 10 can be arranged in an orderly succession abutting against one another with the tags 18 of one holder 10 fitting around the block 14 of the next holder 10 as is clearly shown in FIGURE 3. The block 14 of each holder 10 has a groove 20 formed in its curved surface, the groove 20 extending perpendicularly to the end faces of the block 14.

I'he panel 12 is mounted on an anvil plate 22 which is in turn mounted on a supporting platen 24. The panel Patented Aug. Z9, 1961 12 has formed in it a number of small holes 26 into which the tags 18 of a holder 10 are intended to be inserted, and a number of concave grooves 28 are formed in the upper face of the anvil plate 22, the grooves 28 corresponding in position with the holes 26; the arrangement is such that, with the panel 12 located in position on the platen 24, when the tags 18 of a holder 10 are inserted into the holes 26, the ends of the tags 18 strike the curved surfaces of the grooves 28 and are thereby bent over outwardly against the underside of the panel 12 so as to tix the holder 10 securely in position relative to the panel 12.

The mechanism includes an elongated tubular metal magazine 30 having a circular cross-section except for a longitudinal slot 32 formed in the wall of the magazine 30, and a longitudinal ridge 34, formed adjacent one of the bounding edgesv of the slot 32, projecting into the interior of the magazine 30. When fully loaded, the magazine 30 contains a stackvof about ifty valve holders 10 arranged as described above with the ridge 34 fitting into the grooves 20 of the holders 10; thus, it will be appreciated that thc ridge 34 and the grooves 20' provide a means for ensuring that the holders 10 contained in the magazine 30 are all arranged in the same angular position relative to the magazine 30.

The mechanism also includes a vertically extending support 36 which is adjustably secured to the base (not shown) of the in-line assembly machine. A lixed block 38 is secured to the upper end of the support 36, the -block 38 being formed in to complementary parts 40 4(only one of which is shown in FIGURE 1) which are secured t0- gether by means of bolts 42. A slide block 44 of T- shaped cross-section is slidably mounted in the lixed block 38, the block 44 being a sliding fit in a vertically extending recess" 46, having a cross-section corresponding to that of the block 44, which is formed in the block 38.

A slidable member 48 is disposed above the fixed block 38, the member 48 comprising a bar50 the ends of which are formed integral with two blocks 52. The outer face of each block 52 has a projection 54 formed on it, and the projection 54 are respectively in sliding engagement with two vertically extending slots 56 formed in two parallel vertical plates 58 (only one of which is shown in FIGURE l) projecting upwards from the upper edges of the xed block 38. A second slidable member 60, similar in shape to the member 48, is disposed above the member 48; the slidable member 60 also comprises a bar 62 the ends of which are formed integral with two blocks 64, and two projections 66 are formed on the outer faces of the blocks 64, the projections 66 also being in sliding engagement with the slots 56.

Two circular recesses 68 are respectively formed in the upper faces of the blocks 52, and two further recesses 70 are respectively lformed in the lower faces of the blocks 64. The members 48 `and 60 are urged apart by means of two compressed springs 72, the lower parts of the springs 72 being accommodated in the recesses 68 and the upper parts of the springs 72 being accommodated in the recesses so that the ends of each spring 72 respectively bear against the bases of the relevant pair of

recesses

68 and 70. Movement apart of the

members

48 and 60 is limited by means of two bolts 74 which are slidably mounted with respect to the blocks 64; the Shanks of the bolts 74 extend inside the springs 72 with the ends of the bolts 74 screwed into the blocks 52, while the heads of the bolts 74 normally bear against the upper faces of the blocks 64 thereby determining the furthest distance apart of the

members

48 and 60. It should be appreciated that the combination of the

slidable members

48 and 60 is movable in a vertical direction with respect to the iixed blockv 38 with the

projections

54 and 66 slid- `ing inside the slots 56.

The slide block 44 is connected to the member 48 by means of a vertically extending elongated bolt 78 the lower end of which is screwed into the upper end of the block 44. The shank of the bolt 78 passes through, and is a sliding fit with respect to, a hole 80 formed in the bar 50, and the head 82 of the bolt 78 is disposed between the

bars

50 and 62 thereby limiting the relative movement in a vertical direction between the slide block 44 and the member 48.

A channel member 84 of U-shaped cross-section is secured to the upper end of the xed block 38, the channel member 84 extending horizontally between the support 36 and the two

slidable membersV

48 and 60 with parts of the sides 86 (only one of which is shown in FIGURE l) of the member 84 being disposed between the plates 58. Part of a lever 88 is disposed inside, and extends along the length of, the channel member 84, the lever 88 being pivoted about a spindle 90 the ends of which are respectively secured to the sides 86. A tongue 92 is formed integral with the lower part of that end of the lever 88 adjacent the

members

48 and 60, the tongue 92 being disposed immediately above the bar 62.

A rod 94 is slidably housed in a horizontally extending recess 96 formed in that end of the lever 88 adjacent the

members

48 and 60, and a pawl 98 provided with a chamfered upper surface 99 is lformed integral with one end of the rod 94, the pawl 98 projecting beyond the end of the lever 88. A helical spring 100 is4 compressed between the closed end of the recess 96 and that end of the rod 94 remote from the pawl 98, and an upwardly projecting arm 102 is secured to the rod 94, thel arm 102 passing through a slot 104 in the lever 88 and projecting above the sides S6 of the member 84; the arm 102 and slot 104 serve to locate the rod 94 and the pawl 98 in a xed angular position with respect to the lever 88.

A vertically extending double-acting air cylinder 106 is mounted on a platform 107 secured to the` support 36, and a piston rod 108 is attached to a piston (notn seen) associated with the cylinder 106, the piston rod 108 extending in a vertical direction from the upperend of the cylinder 106. The upper end of the piston rod 108 is pivotally linked to that endof the lever 88 remote from the pawl 98 so that the lever 88 is pivoted about the spindle 90 upon movement of the piston rod 108.

A vertically extending hole 110 is formed in the block 38, the hole 110 being of substantially circular crosssection and communicating with the narrow part of the recess 46. A vertically extending rod 112 is disposed partly inside, and is a sliding tit with respect to, the hole 110, the rod 112 being located in a xed angular position with respect to the block 38 by virtue of a longitudinal ridge 114 formed in the bounding wall of the hole 110 engaging in a longitudinal `groove 116 formed in the rod 112. The rod 112 also passes through, and is a sliding t with respect to, a bush 1.18 which is secured to the lower part of the narrow portion of the slide block 44, part of the wall of the bush 118-being located in a recess 120 formed in this portion of the block 44. The bore of the bush 118 tapers inwardly from the lower end'of the bush 118, the tapered portion being terminated at its upper end by means of a circumferential shoulder 122; the mean diameter of the tapered part of the bore of the bush 118 is equal to the outer diameter of the magazine 30.

A series of teeth 124 are formed on the rod 112, the series of teeth 124 extending longitudinally for most of the length of the rod 112 and facing the support 36. The spacing of the teeth 124 is equal to the spacing ofthe valve holders when housed in the magazine 30, and the arrangement is such that the pawl 98 is normally held in resilient engagement with the rod 112immediately above one of the teeth 124 by means of the spring 100. It should be appreciated that the pawl 98 and the teeth 124 'constitute a ratchet and pawl mechanism connecting the rod 112 to the adjacent end of the lever 88. An arm 126 is secured to the upper end of the rod 112.

A bracket 128 is secured to the lower part of the support 36, the bracket 128 incorporating a horizontal support plate 130. A rectangular movable plate 132 is disposed beneath the support plate 130, and two vertically extending rods 134 are secured to the movable plate 132, the rods 134 projecting upwardly from the plate 132 and passing through, and being a sliding t with respect to, two holes (not seen) 4formed in the support plate 130. Two bushes 136 are respectively secured around those parts of the rods 134 adjacent the plate 132, while two circumferential flanges 138 are formed integral with the upper ends of the rods 134. The movable plate 132 is capable of being moved in a Vertical direction relative to the support plate 130, and the plate 132 is urged towards the plate by means of `four tensioned springs 140 being respectively secured to the

plates

130 and 132; it should be understood that upward movement of the plate 132 relative to the plate 130 is limited by virtue of the upper ends of the bushes 136 coming into contact with the lower -face of the plate 130, and that downward movement of the plate 132 relative to the plate 130 is limited by virtue of the anges 138 coming into contact with the upper face of the plate 130.

A bush 142 projects beneath the movable plate 132, the upper end of the bush 142 being formed as a wider portion 144 part of which is a rotatable tit within a circular hole 146 centrally formed in the plate 132. The upper end of the portion 144 is provided wtlh a circumferential flange 148 which bears against the upper face of the plate 132, and the bush 142 is normally held in a xed angular position with respect to the plate 132 by means of two bolts 150, the flange 148 being trapped between the heads of the bolts 150 and the upper face of the plate 132.

-Four small steel balls 152 are respectively mounted in four recesses 154 formed in the wall of the bush 142, the centres of the balls 152 lying in a horizontal plane spaced from the lower end of the bush 142 by a distance approximately equal to the thickness of the block 14 of a valve holder 10. The recesses 154 are so shaped that each ball 152 is capable of a limited radial movement with respect to the bush 142. Normally, the balls 152 project partly inside the bush 142, and the balls 152 are urged into this position by means of four generally vertically extending leaf springs 156, the upper ends of which are securedl to the bush 142 by means of screws 158 and the lower ends of which respectively bear against the outermost parts of the yballs 152; each ball 152 is constrained by the bounding wall of the relevant recess 154 so as to prevent the ball 152 being forced by the relevant spring 156 wholly into the interior of the bush 142.

' 'Ihe magazine 30 is mounted in the mechanism with its axis vertical and with the tags 18 of the valve holders 10 mounted in the magazine 30 pointing downwardly. The lower end of the magazine 30 fits into the upper portion 144 of the bush 142, this end of the magazine 30 abutting against a circumferential shoulder 160 formed in the inner surface of the bush 142; the diameter of the bore of the bush 142 below the shoulder 160 is equal to the internal diameter of the magazine 30, while the diameter'of that part of the bore of the bush 142 above the shoulder 160 is equal to the outer diameter of the magazine 30. The magazine 30 is located in a xed angular position with respect to the bush 142 by means of a longitudinally extending ridge 162 formed on the inner surface of the portion 144 of the bush 142, the ridge 162 engaging in a longitudinal groove 164 formed in the outer surface of the magazine 30. When a loaded magazine 30 is inserted into the upper end of the bush 142, the tags 18 of the lowermost component 10 contained in the magazine 30 project below the magazine 30, and, in order to facilitate the insertionrof thesetags, 18 into the bush 174,2, a number of grooves 166,l corresponding in position to the tags 18, yare formed in the upper part of 'we i rrr r r the-bush 142 adjacent the bore of'the bush 142, the groovesV 166 sloping inwardly and downwardly from the upper surface of the bush 142V. It should be understood that the Ibush 152 and the magazine 30 together form a container for the holders 10, and that normally a few holders 10 are housed in the bush 1-42 while the remainder of the holders 10V are housed in the magazine 30. In the-condition shown in FIGURE 3 the magazine 30 is empty and all the holders 10 contained in the abovementioned container are housed in the bush 142,

The upper end of the magazine 30 is housed in the bush 118, Kand nor-rnally this end of the magazine 30 is caused to bear resiliently against the inner surface of the bush 118 under the action of the springs 140.

When the magazine 30 is empty, it can be removed from the mechanism and replaced by a loaded magazine 30 as follows The arm 102 isV moved from right to left (with respect to FIGURE 2) soras to disengage the pawl 98 from the teeth 124 of the rod 112. The rod 112 is then lifted upwardly by means of the arm 126 to a position in which its lower end is above the lower end of the bush 118, yand the movable plate 132 is depressed to its fullest extent, while the slide block 44 is held in its uppermost position, thereby bringing the upper end of the magazine 30 below the lower end of the bush 118. The empty magazine 30 is now removed and replaced by a loaded magazine 30. The movable plate 132 is then allowed to return to its uppermost position, the rod 112 is lowered until its lower end abuts against the uppermost valve holder 10 in the magazine 30, and the arm 102 is released thereby allowing the pawl 98 to return into engagement with the rod 112.

The operation of the mechanism will now be described. The printed circuit panel 12 is moved into the desired position beneath the bush 142 while the piston rod 108 is in its lowermost position; while the piston rod 108 is in this position, the assembly of the movable plate 132, the bush 142 and the magazine 30 is in its uppermost position, the slide block 44 and the slidable members 4S and 60 are also in their uppermost positions with the bar 62 resting on the head 82 of the bolt 78, the lowermost valve holder 10 in the bush 142 rests on top of those parts of the balls 152 projecting inside the bush 142, the lower end of the rod 112 abuts against the uppermost valve holder 10 in the magazine 30, and the pawl 98 is in engagement with one of the teeth 124.

Upon the commencement of the upward stroke of the piston rod 108, the lever 88 is pivoted in a clockwise direction (with respect to FIGURE 2) so that the pawl 98 forces the rod 112 downwards. The pressure exerted by the leaf springs 156 on the balls 152 is sulicient at this stage to prevent the lowermost valve holder 10 from moving downwardly past the balls 152, so that downward movement of the rod 112 also brings about a downward movement of the plate 132, the bush 142 and the magazine 30; it should be appreciated that, as the magazine 30 moves downwards, the slide block 44 and the

slidable members

48 and 60 also move downwards under gravity so that the bush 118 remains in Contact with the upper end of the magazine 30. The downward movement of the assembly of the movable plate 132, the bush 142 and the magazine 30 continues until the flanges 138 come into contact with the upper face of the plate 130 thereby causing the downward movement of the bush 142 to be arrested; at this stage the arrangement is as shown in FIG- URE 3 of the drawings, the lower end of the bush 142 touching the panel 12. Also, at this stage, the slide block 44 and the

slidable members

48 and 60 have reached their lowermost positions as shown in FIGURE 2, the bar 50 of the member 48 resting on top of the fixed block 38 and the head 82 of the bolt 78 resting on top of the bar 50.

Thereafter, `downward movement of the rod 112 continues and the stack of holders 10 moves downwardly relative :to the magazine 30 and -the bush 142, the-lowermost holder 10 being forced past the balls 152 Ythereby causing the balls 1'52 -to be moved outwardly against the pressure exerted by the leaf springs 156.- The ends of the tags 1S of the lowermost holderY 10 are caused to pass through the holes 26.in the panel `:l2 and to be bent over outwardly against the underside of the panel 12 by virtue of their being pressed against 'the grooves 28 formed in the anvil -plate 22; at this stage the piston rod 10S is in its uppermost position and the arrangement is as shown in FIGURE 2. The upper edge of each holder 10 is chamfered as -is clearly shown in FIGURE 3 so that at this stage the balls 152 again project into the bush 142, that holder 10 adjacent the holder 10 is just mounted on the panel 12 bearing downwardly onf fthe balls 152 so as to retain the assembly of the bush 142, `the movable plate 132 and the magazine '30 in its lowermost position. Just prior to the rod 112 reaching its lowermost position, the tongue 92 formed on the lever 88 comes into contact with the bar 62, vand the Yremainder of the downward movement of-the tongue 92 brings .about a slight downward movement of the'bar 62 against the pressure exerted by the springs 72.

Upon the commencement of rthe downward stroke of the piston rod 108, the lever 88 is pivoted in -an anti-clockwise direction (with respect to FIGURE 2) thereby allowing -the assembly of the bush 142, the movable plate 132, the magazine 30 and the rod 112 to move upwards with the pawl 98 under the action of the springs 140; it will be appreciated that the balls 152 retain the stack of holders 10 remaining in the bush 142 and the magazine 30 in position relative to the bush 142 and the magazine 30. Also, upward movement of the magazine 30 causes the slide block 44 to move upwards which in turn causes the

members

48 and 60 to move upwards, the head 82 of fthe bolt 78 bearing against the bar 62. The upward movement of the yassembly of the bush 142, the movable plate 132, the magazine 30, the rod 112, the slide block 44 and the

slidable members

48 and 60 continues until the bushes 136 come into contact with the lower face of the iixed plate 130, and thereafter the pawl 98 moves upwards relative to this assembly until the piston rod '108 reaches its lowermost position, the weight of the rod 112 being Suicient to overcome the resistance of the spring 100 and thereby prevent further upward movement of the rod 112. During this relative movement of the pawl 98 with respect to the rod 112, the pawl 98 slides upwards over one tooth 124 of the rod 112, and it should be appreciated that at the end of this cycle of operation -the position of the rod 112 will be lower than its position -at the beginning of the cycle of operation by a distance corresponding to the spacing of the valve hol-ders 10 in the magazine 30. Thus, at the commencement of fthe next upward stroke of the piston rod 108 the pawl 98 engages with that tooth 124 immediately above the tooth 124 engaged by the pawl 98 during the immediately preceding cycle of operation.

After a short interval, the next printed circuit panel is moved into position lbeneath the mechanism and the cycle, of operation is repeated.

It will be appreciated that, in operation of the mecha-v nism, the length of the stroke of the rod 108 remains substantially constant, so ythat 4the pressure exerted on the stack of holders 10 while a holder 10 is being inserted into a printed circuit panel also remains substantially constant from one cycle of operation to the next. Also, it lshould be appreciated that, in the mechanismv described above, the length of the stroke of the piston rod 108 can be arranged to be relatively short thereby enabling the dura-tion of each cycle of operation of the mechanism to be made relatively short. On the other hand, if the piston rod 108 were arranged to act directly on the stack of holders 10, -the -rod 108 would not exert constant pressure on the stack of holders 10, While the length of the stroke of the piston rod 108 would increase for each successive cycle of operation.

I claim:

1. A feed mechanism for use in mounting articles on support members, said mechanism including a container which is elongated and is open -at both ends, the container being vadapted to contain a plurality of similar articles abutting 4against one Ianother in an orderly succession extending along the length of the container, a ram which is arranged to bear against an end one of the succession of articles, a reciprocable member which in operation has a substantially constant length of stroke and which is coupled to the ram -by a linkage at least partly constituted by a ratchet and a pawl mechanism whereby during each forward stroke of the reciprocable member the articles -in Ithe container are pushed lengthwise through the container over a distance substantially equal to the spacing of the articles in the container, and power means for reciprocating said reciprocable member.

2. A feed mechanism according to claim l, in which at least a major pant of the container is readily removable from the remainder of the mechanism.

3. A feed mechanism according to claim 1, including References Cited in the file of this patent UNITED STATES PATENTS 1,169,775 Cornwall Feb. l, 1916 2,073,328 Wasserlein Mar. 9, 1937 2,220,354 Nov. 5, 1940 2,544,499 Hovey Mar. 6, 1951 2,718,299 Sept. 20, 1955 2,843,923 July 22, 1958 2,879,585 Petersen Mar. 31, 1959