GB2197806A - Automatic apparatus for the production of stationary contacts for electromagnetic relays - Google Patents

Abstract

A strip (12), on which a succession of contacts (1) has been made by prepunching, is conveyed to a first operating unit (10) for checking the presence of the strip. A second operating unit (16) feeds contact points (5) from a container along a guide to a third operating unit (18) which picks them up by a pivoting arm and places them in holes (4) provided on the contacts (1). A fourth operating unit (20) with upper and lower dies rivets the contact points (5) to the strip (12) and a fifth operating unit (24) advances the strip (12) by predetermined steps. A sixth operating unit (26) checks the presence of the contact points (5) on the contact (1) and a seventh operating unit (28) has upper and lower dies to bend contact pins (3) arranged at one end of the contact (1). The described apparatus is particularly useful for high speed production of stationary contacts. <IMAGE>

Description

"AUTOMATIC APPARATUS FOR THE PRODUCTION OF STATIONARY CONTACTS FOR ELECTROMAGNETIC RELAYS" This invention relates to automatic apparatus for the production of stationary contacts for electromagnetic relays.

In the present specification, the term "contact" is intended to denote an element adapted to establish and interrupt the continuity of an electric circuit. Such a contact is made substantially of metallic material of high electric conduction and is provided upwardly with a contact point, with a central body formed by a rigid blade, and downwardly with a contact pin having an end with a rounded point.

The process for making electrical contacts used in electromagnetic relay, particularly in relays for printed circuits,has been known for a long time. Conventionally this process comprises a substantially manual method by which blades of appropriate shape are made by punching operations from a metal strip. To the upper portion of these blades then a contact point is secured by a riveting operation using appropriate dies mounted in a press.

In a further operating step, also carried out manually, the contact pin formed by the lower portion is bent according to the angles required by the specific use, using high speed presses.

The manual process of making contacts for electrical relays, described above, is not only lengthy but also extremely uneconomical because of the considerable amount of manpower employed in the successive operating steps.

Further, the numerous manipulations to which the contact is subjected in the various operations produce a relatively thick surface layer of oxidations which requires special cleaning operations.

From the foregoing explanations it is evident that making contacts for electromagnetic relays according to the method described above sets considerable limitations to the high outputs required for this particular type of product and makes it uneconomical, as explained above, and thus certainly not competitive.

It is therefore an object of the present invention to eliminate or reduce the disadvantages and drawbacks of contacts made by manual cycles of production and to provide apparatus for automatically making contacts for electromagnetic relays in a rational cycle of operations and in successive steps.

It is a further object of the present invention to limit the manual work of the operator to the maintenance of the apparatus, thus avoiding direct operations on the contacts being made.

Consequently, the contacts thus made will be exempt from harmful and dangerous surface oxidations and will be ready for the following steps of mounting the relay.

A last but not least object of the present invention is to permit a substantial reduction of production costs as the use of the present apparatus will permit a drastic reduction of manpower that has hitherto been used in the individual operating steps, and simultaneously also a reduction of the production times is obtained.

The above and other objects and advantages of the present invention, which will become apparent from the following description, are achieved according to the invention by automatic apparatus for the production of stationary contacts for electromagnetic relays, by which apparatus the operating steps start with the use of a metal strip carrying a succession of prepunched contacts provided with holes at one end and equally spaced central holes, this apparatus being characterized in that it comprises in succession:: a) a first operating unit for detecting the presence of the strip, said first operating unit being formed by means for supporting the strip and means for detecting the presence of the strip; b) a second operating unit for feeding contact points, said second operating unit being formed by a vibratory device of circular shape and by guide means for the points;; c) a third operating unit for positioning the contact points in a die arranged in a riveting press, said third operating unit comprising a swing arm pivotally mounted in its centre and actuated by pneumatic means arranged perpendicularly to one another to act on said arm along their axes of movement, said swing arm being arranged parallel to and above the plane of movement of said strip and the plane of feeding of said contact points at a distance not greater than the thickness of said points, said swing arm being further provided with a seat for receiving said contact points and translating them along said plane up to a recess located in a riveting dolly to release said contact points in said dolly by swinging around the central pivot of said swing arm;; d) a fourth operating unit for riveting said contact points, said fourth operating unit comprising a hydraulic actuator having its ends secured to a metal carpentry structure, a downwardly acting rod mounted for reciprocating movement in said hydraulic actuator and firmly connected to a riveting die; a pneumatic actuator arranged in a vertical position opposed to said hydraulic actuator; an upwardly acting rod arranged for alternating movement in said pneumatic actuator to engage said metal strip for lifting it from its plane of movement; e) a fifth operating unit for pulling said strip, said fifth operating unit comprising a first pneumatic actuator for gripping said strip and second actuators actuated intermittently in the direction of feed of the strip, said first actuator alternately releasing said strip and one of said second actuators being actuated in the opposed direction for returning to the starting position;; f) a sixth operating unit for detecting the presence of the contact point riveted to the strip, said sixth operating unit comprising sensor means for checking the presence of the point, and g) a seventh operating unit for bending the contact pin, said seventh operating unit comprising a hydraulic actuator having its ends secured to a metal carpentry structure, and a rod mounted for reciprocating movement in said hydraulic actuator to act downwardly on a bending die.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a contact according to the invention without contact point; Fig. 2 shows a contact point before being inserted in and riveted to the contact of Fig. 1; Fig. 3 shows a prepunched strip portion as used before starting the operating steps with the apparatus according to the present invention; Fig. 4 is a block diagram showing the individual operating units of the apparatus according to the invention as arranged in the order of their successive operating steps; Fig. 5 is a perspective view of the assembly of the operating units forming the apparatus according to the invention; Fig. 6 is a side view of the device for detecting the presence of the movable strip according to the invention; ; Fig. 7 is a top plan view of the unit for feeding the contact points and the operating unit for feeding them to the riveting press according to the invention; Fig. 8 is a side view of the operating unit for feeding the contact points of fig. 7; Fig. 9 is a side view of a lever for picking up the contact points in the feeding unit of Fig. 8; Fig. 10 is a plan view of the lever of Fig. 9; Fig. 11 is an elevational view of the riveting press and unit for lifting the strip according to the invention; Fig. 12 is an elevational view of the unit for pulling the strip according to the invention; Fig. 13 is a top plan view of the pulling unit of Fig. 12;; Fig. 14 is an elevational view of the unit according to the invention for checking the presence of the point on the strip after the riveting operation, and Fig. 15 is a side view of the press and die according to the invention for bending the contact pin.

The automatic apparatus for the production of stationary contacts for electromagnetic relays according to the invention basically is composed of a series of individual operating units which operate in successive steps on a prepunched strip indexed between the individual operating units.

Fig. 1 shows a contact indicated by an arrow and the numeral 1 and formed by a central body 2, normally indicated by the technical term "blade", by a contact pin 3 and a hole 4 which forms the seat for a contact point 5, the latter being shown in Fig. 2.

For greater clearness the contact point 5 is shown in Fig. 2 on a larger scale than the contact 1 in Fig. 1.

Fig. 3 shows a strip portion in which the prepunched contacts 1 can clearly be seen, these contacts being connected by a central band 6 in which equidistantly spaced holes 7 are provided for being gripped during the sequence of operations by a pulling unit for stepwise advancing of the strip through the interior of the apparatus forming the subject matter of the present invention.

For a better understanding of the present invention, Fig. 4 shows in a block diagram the individual operating units which perform the following functions: A first operating unit 10 checks whether a prepunched strip 12 coming from a conventional winding reel 14 is not interrupted and is steadily advancing in the longitudinal direction under the action of a pulling unit which will be described hereinafter.

The prepunched strip 12 is normally supplied in coils of considerable length, ready to be placed on a winding reel denoted by the numeral 14 in Fig. 4.

A second operating unit 16 for feeding the contact points 5 conveys them in an orderly manner to a third operating unit 18 which inserts them into the holes 4 arranged in the blades 2 of the contacts 1.

A fourth operating unit 20 rivets the contact point 5 which was previously inserted into the contact by the unit 18 while a device 22 forming part of the fourth unit 20 lifts the strip at the end of this riveting step.

A fifth operating unit 24 pulls the strip 12 in the longitudinal direction and causes it to advance by steps corresponding to the distance between the prepunched contacts on the strip 12.

A sixth operating unit 26 checks whether the contact point 5 has been regularly inserted and riveted to the hole 4 in the contacts 1 on the strip 12. If the unit 26 should detect that a point 5 has not been inserted into the corresponding contact 1, the unit 26 would stop the apparatus by appropriate means which will be described hereinafter, thus permitting an operator to remove the cause of the defect.

A seventh operating unit 28 bends the contact pin 3 of the contact 1 and gives it the desired shape.

Referring to Fig. 5, the automatic apparatus for the production of stationary contacts for electromagnetic relays is basically formed by a carpentry structure 30 of parallelepiped shape, which on a table 32 carries, and has firmly secured thereto, the various operating units whose functions have been described above.

Further, arranged in the interior of the structure 30 are service means such as solenoid valves, air and oil distributors, push-button panels, etc., not shown, as they are known to one skilled in the art.

The first operating unit 10 for checking the strip, which is shown in detail in Fig. 6, is essentially formed by a support 34 secured to the table 32 of the structure 30.

Secured to the upper portion of the support 34 is a sensor normally formed by a limit switch 36 - or other similar means such as a proximity switch, magnetic sensor or the like - which checks the presence of the strip and switches off the following units if, for some reason or other, the strip should be missing.

The second operating unit 16 for feeding the contact points 5 is shown in detail in Fig. 7 and is formed by a cylindrical container 38 in the interior of which the points 5 are arranged.

The cylindrical container 38 is set into vibration by means not shown, as they are known to one skilled in the art, and conveys the contact points 5 along a guide 40 to a feeding unit which positions the points in the interior of the holes in the contact moving below the riveting unit 20.

The third operating unit 12 for feeding the contact points 5 is shown in detail in Figs. 7 and 8 and is formed by an air cylinder 42 actuated by means not shown. A rod 44 is movably mounted in the interior of the air cylinder 42.

A bracket 46 is centrally secured to the forward end of the rod 44 extending from the cylinder 42. A pair of guide rods 48 and 48' are secured to the lateral ends of the bracket 46 and are movable in parallel along the axis of the cylinder 42 and are guided in this movement in the interior of a U-shaped bracket 49.

At the opposite end the guide rods 48 and 48' are secured to a bracket 50 which facilitates their parallel movement.

An arm 54 is pivotally mounted at 52 on the bracket 46 for picking up the contact points 5 from the guide 40 and feeding them to the riveting unit 20.

The arm 54 is shown in two views in Figs. 9 and 10 and formed by an appropriately shaped metal segment which can swing around the fulcrum 52. A semicircular seat 59 is made at one end of the arm 54 and is shaped according to the type of point that it is intended to receive, this seat being adapted to engage and slidingly translate the point on to the same plane of movement of the strip 12.

A threaded shaft 56 is secured with one end to the rear end of the cylinder 42 and at the other end terminates with a pair of locked nuts to form a member for adjustment of the stroke of the rod 44.

Movably mounted in the interior of the air cylinder 58, which is actuated by means not shown, is a rod 60 which, as it is extended, acts on one end of the arm 54 and forces the latter to release the point 5 places into one of the holes of the contacts forming the strip 12.

The fourth operating unit 20 for riveting the contact points 5 is shown in Fig. 11 and is formed by a hydraulic actuator 61 whose cylinder 62, which is actuated by means not shown, is secured to the interior of a peripheral carpentry structure 64.

The structure 64 is supported on the table 32 of the structure 30 and is firmly secured to the latter by appropriate means, not shown.

Secured to one end of a rod 70, which is movably mounted in the interior of the cylinder 62, is an upper die 66 which, as it approaches a lower die 68 also arranged in the interior of the structure 64, produces riveting of the point 5 that has previously been placed into the respective contact by the feeding unit 18.

Riveting of the contact points 5 arranged in the individual contacts 1 is carried out one by one, i.e. one point after another in synchronism with the step-by-step movements produced by the pulling unit 24 which will be described hereafter.

Referring again to Fig. 11, an air cylinder 72 is arranged below the lower die 68 and through its rod 74, which is movably mounted in the interior of the cylinder 72, acts on the strip 12 causing it to be lifted from its plane of movement and to be removed from the lower die at the end of the riveting operation.

In this manner the strip 12 can advance as it is pulled by the pulling unit 24 which acts at the end of each individual riveting operation.

The fifth operating unit for pulling the strip is indicated by 24 in Fig. 5 and is shown in detail in Fig. 12. It basically consists of an air cylinder 76 arranged in a vertical position and anchored downwardly to a support 78. The support 78 is of inverted U-shape with the lower portion connected to a bracket 80 which moves longitudinally in the direction of advance of the strip 12 on a pair of guides 81 shown in Fig. 13 and arranged in parallel with a pair of cylinders 84 and 86 which in turn are arranged below the plane of movement of the strip 12.

A pneumatic actuator 75 is formed by an air cylinder 76 in the interior of which a rod 77 is movably mounted. A push rod 82 is arranged at the outlet end of the rod 77 and engages in succession each of the holes 7 in which it is inserted. The holes 7 in turn are arranged at equal distances from one another in the band 6 of the strip 12.

A pair of pneumatic actuators 85 and 87 formed by the air cylinders 84 and 86, respectively, are secured inwardly to a support bracket 83. The bracket 83 is in turn connected to the table 32 of the structure 30 by appropriate fixing means, not shown.

The rod 88 of the cylinder 84 is connected to the bracket 80 and as the rod is extended or retracted it imparts a reciprocating movement to the bracket 80. Consequently, the strip 12, as it is engaged as previously described by the push rod 82 of the cylinder 76, is pulled along its horizontal axis of movement.

The cylinder 86, which is arranged parallel to and downwardly of the cylinder 84, is made whith a greated diameter than the latter and, as both cylinders are fed by the same air pressure, the former will develop a greater power which will make the bracket 80 stop in its advance movement against a push rod 90 placed at the end of the rod 92 of the cylinder 86.

In this manner a first indexing advance movement "A" is imparted to the strip 12, which corresponds to the distance between one contact and another, as illustrated in Fig. 3.

Actuation of the cylinder 86 causes the rod 92 to retract and as the latter releases the bracket due to the momentary stop produced by the push rod 90, the rod 92 permits the bracket 80 to carry out a further shifting movement in the direction of advance of the strip 12.

In this manner a second indexing advance movement "B" is imparted to the strip 12, which corresponds to a distance different from the distance between one contact and another, as illustrated in Fig. 3.

At the end of this second advance movement, the rod 77 is retracted into the cylinder 76 and releases the push rod 82 from its engagement with the strip 12, thus permitting the cylinder 84 to extend the rod 88 and return the bracket 80 secured to the support 78 to the initial position.

Fig. 14 shows in detail the sixth operating unit for checking the presence of the riveted point, this unit being also indicated in Fig.

5 by numeral 26. This unit, which is arranged immediately after the pulling unit 24, is substantially formed by a support 94 of inverted U-shape, which is downwardly connected to a plane bracket 96 in turn secured to the upper surface of the support bracket 83.

The strip 12 runs longitudinally through the interior of the Ushaped support 94.

An air cylinder 98 is anchored to the upper portion of the support 94 and has a rod 100 on which a feeler push rod 102 is mounted whose diameter is smaller than that of the hole 4 which forms the seat for the contact point 5.

Further, a sleeve 104 is slipped on to the rod 100 and locked thereon by means not shown. A pair of abutments 106 and 106' projecting from the sleeve 104 actuate a limit switch 108 when the push rod 102 does not stop on the contact point 5 riveted to the contact 1, but continues its path through the hole 4.

Actuation of the limit switch will automatically stop the apparatus and attract the attention of the operator for removing the defect.

Fig. 15 shows in detail the seventh operating unit for bending the contact pins 3. This unit is also indicated in Fig. 5 by numeral 28.

A hydraulic actuator 109 formed by a hydraulic cylinder 110 and actuated by means not shown,is secured to the interior of a peripheral carpentry structure 112. The structure 112 is supported on the table 32 of the structure 30 and is firmly connected to the latter by appropriate means, not shown.

A pair of cross connection beams 114 and 116 shown in Fig. 5 are interposed between the structure 64 and the structure 112 to impart greater rigidity to the connection between these two structures.

An upper die 120 is secured to one end of a rod 118 movably mounted in the interior of the cylinder 110 and, as the upper die 120 approaches a lower die 122, likewise arranged in the interior of the structure 112, it causes bending of the contact pins 3.

The operation of the operating units forming the apparatus according to the present invention is as follows: After the strip 12 has been inserted into the unit 10 for checking the presence of the strip, the latter sets the following units for operation. Then the strip is conveyed to the feed unit 18 which picks up one by one the contact points 5 from the feed unit 16 and places them into the holes 4 in the contacts 1 arranged along the strip 12.

The riveting unit 20 rivets the points placed into its dies. At the end of this step, the pulling unit 24 shifts the strip 12 by one step corresponding to the distance between one contact and another. In this manner a further new contact 1 is presented to the feed unit 18 for insertion of a new contact point 5.

At the end of the pulling step, the unit 26 checks if the step of riveting the point has been correctly carried out and, if this is the case, permits the various units to continue the operation.

Simultaneously with the pressing step also the step of bending of the contact pin by the unit 28 is carried out.

The invention is not limited to the specific embodiment that has been described and illustrated, but is liable to numerous modifications and variations within the scope of the same inventive idea. The scope of the invention is more exactly defined by the accompanying claims.

Claims (13)

1. Automatic apparatus for the production of stationary contacts for electromagnetic relays, by which apparatus the operating steps start with the use of a metal strip (12) carrying a succession of prepunched contacts provided with holes (4), at one end, and central holes (7) equidistantly spaced this apparatus being characterized in that it comprises in succession:: a) a first operating unit (10) for detecting the presence of the strip (12), said first operating unit being formed by means (34) for supporting the strip and means (36) for detecting the presence of the strip; b) a second operating unit (16) for feeding contact points (5), said second operating unit being formed by a vibratory device of circular shape and by guide means (40) for the points;; cj a third operating unit (18) for positioning the contact points (5) in a die (66, 68) arranged in a riveting press, said third operating unit (18) comprising a swing arm (54) pivotally mounted in its centre at (52) and actuated by pneumatic means (42, 58) arranged perpendicularly to one another to act on said arm (54) along their axes of movement, said swing arm (54) being arranged parallel to and above the plane of movement of said strip and the plane of feeding of said contact points (5) at a distance not greater than the thickness of said points, said swing arm being further provided with a seat (59) for receiving said contact points and translating them along said plane up to a recess located in a riveting dolly (68) to release said contact points in said dolly by swinging around the central pivot of said swing arm;; d) a fourth operating unit (20) for riveting said contact points (5), said fourth operating unit comprising a hydraulic actuator (61) having its ends secured to a metal carpentry structure (64), a downwardly acting rod (70) mounted for reciprocating movement in said hydraulic actuator (62) and firmly connected to a riveting die (66, 67); a pneumatic actuator (72) arranged in a vertical position opposed to said hydraulic actuator (61); an upwardly acting rod (74) arranged for alternating movement in said pneumatic actuator (72) to engage said metal strip (12) for lifting it from its plane of movement; e) a fifth operating unit (24) for pulling said strip, said fifth operating unit comprising a first pneumatic actuator (75) for gripping said strip and second pneumatic actuators (85, 87) actuated intermittently in the direction of advance of the strip, said first actuator (75) alternately releasing said strip (12) and one of said second actuators (85) being actuated in the opposed direction for returning to the starting position;; f) a sixth operating unit (26) for detecting the presence of the contact point (5) riveted to the strip, said sixth operating unit comprising sensor means (108) for checking the presence of the point, and g) a seventh operating unit (28) for bending the contact pin (3), said seventh operating unit comprising a hydraulic actuator (109) having its ends secured to a metal carpentry structure (112), and a rod (118) mounted for reciprocating movement in said hydraulic actuator (109) to act downwardly on a bending die (120, 122).

2. Apparatus as claimed in claim 1, characterized in that said sensor means (36) is formed by a limit switch.

3. Apparatus as claimed in claim 1, characterized in that said pneumatic means (42, 58) are formed by air cylinders each having a rod (44, 60) movably mounted in the interior thereof.

4. Apparatus as claimed 1, characterized in that said riveting die (66, 68) is formed by an upper die (66) and a lower die (68).

5. Apparatus as claimed in claim 1, characterized in that said pair of rods (48, 48') form guide members for a bracket (46) arranged for reciprocating movement by means of a rod (44).

6. Apparatus as claimed in claim 1, characterized in that a threaded shaft (56) forms a member for adjustment of the stroke of the rod (44) of the cylinder (42).

7. Apparatus as claimed in claim 1, characterized in that a hydraulic actuator (61) is formed by a hydraulic cylinder (62) and a rod (70) movably mounted in said cylinder.

8. Apparatus as claimed in claim 1, characterized in that a pneumatic actuator (75) is formed by a cylinder (76) and a rod (77) movably mounted in said cylinder.

9. Apparatus as claimed in claim 1, characterized in that a pneumatic actuator (85) is formed by a cylinder (84) and a rod (88) movably mounted in said cylinder.

10. Apparatus as claimed in claim 1, characterized in that a hydraulic actuator (87) is formed by a cylinder (86) and a rod (92) movably mounted in said cylinder.

11. Apparatus as claimed in claim 1, characterized in that said sensor means (111) for checking the presence of the contact point (5) is formed by a feeler push rod (102) arranged to actuate a limit switch (108).

12. Apparatus as claimed in claim 1 characterized in that a hydraulic actuator (109) is formed by a cylinder (110) and a rod (118) movably mounted in said cylinder.

13. Apparatus for the production of stationary contacts for electromagnetic relays substantially as hereinbefore described with reference to and as illustrated by the accompanying drawing.