Narrow aerial and die-mount cams

Narrow aerial and die-mount cams, each having a cam adapter, a driver and a slide sandwiched between the cam adapter and driver. The narrow aerial cam slide has an elongate primary portion that has a T-shaped cross-section and has a primary bearing surface, and the cam adapter has a rectangular recess. An elongate keeper plate having a longitudinal slot is secured to each side of the cam adapter adjacent the rectangular recess to slidably retain the primary portion of the slide within the longitudinal slots and the rectangular recess. The primary bearing surface and a pair of intermediate bearing surfaces formed in the slide below the primary portion slidably support the keeper plates and thus the cam adapter. The driver slidably supports the slide. The narrow die-mount cam is basically an inverted version of the aerial cam.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to aerial and die-mount cams and more particularly to improvements in cams configured to provide an increased load-bearing capacity and to facilitate the fabrication of long-lived, narrow cams having components that do not require custom fitting.

2. Background Art

Aerial and die-mount cams are often used to operate tools for such manufacturing processes as punching, trimming, stamping and bending workpieces. These devices include elements that convert downward and upward forces provided by a press into laterally directed component forces that advance and retract a tool in lateral directions to effect the mentioned processes.

Since some manufacturing processes require the application of considerable forces, an important feature of cams is their load-bearing capacity. Cams in present use typically have a maximum load-bearing capacity of some 1.5 tons. Previous attempts to increase load-bearing capacity have included broadening bearing surfaces, but these have increased the width of the cams. Since cam size is a limiting factor that prohibits the use of certain cams in certain presses and for certain applications, it is thus another important feature in cam design and application.

A few of the attempts to increase load-bearing capacity of cams have included the introduction of laterally inclined bearing surfaces. These changes provided an advantage of increasing the stability of the cams as well as somewhat increasing their load-bearing capacities, but they were not directed toward reducing the lateral sizes of cams.

The wearing of parts that are in slidable contact with other parts is always a concern in mechanisms such as aerial and die-mount cams. Having to remove cams from their presses to replace worn parts can be a costly and time-consuming activity.

The structural integrity of joined parts is another important area of concern. Fasteners such as bolts that hold parts together are more likely to loosen or fail if they are placed under stress during press operation.

Many aerial and die-mount cams have configurations that are unique to their use in specific presses and for specific purposes. Their design and construction result in additional expenses.

SUMMARY OF THE INVENTION

An object of the present invention is to provide improved aerial and die-mount cams that have a more efficient load distribution. The improved load distribution enables the cams to be narrower and to bear an increased load.

In carrying out the foregoing object, the aerial and die-mount cams each include a driver, a slide and a cam adapter arranged in vertically stacked relation. The cams have slidably arranged bearing surfaces between the driver, slide and cam adapter supporting the same for relative sliding movement upon closing and opening of platens of a press between which the cam may be arranged.

Each of the slidably arranged bearing surfaces cooperatively extend continuously across the distance between opposite sides of the driver, slide and cam adapter. The loading on the cam is therefore distributed across the entire width of the cam.

At least a portion of the bearing surfaces spacedly overlap each other, and the bearing surfaces extending between opposite sides of the cam thereby cumulatively exceed the distance between the opposite sides. This facilitates the fabrication of cams that not only have greater load-bearing capacities but also cams that are narrower and whose slides have increased angular stability.

The driver has a driver bearing surface, and the slide has a primary portion and a secondary portion. The primary portion has a T-shaped cross-section and an elongate primary bearing surface, and the secondary portion has a secondary bearing surface in slidable contact with the driver bearing surface. The slide further has a pair of parallel and laterally spaced intermediate bearing surfaces located intermediate the primary bearing surface and the secondary bearing surface. The driver bearing surface is softer than the secondary bearing surface and is formed of self-lubricating material.

The cam adapter has a rectangular recess; and each of a pair of elongate keeper plates, each having a longitudinal slot, is secured to one side of the cam adapter adjacent the rectangular recess to slidably retain the primary portion of the slide within the longitudinal slots and the rectangular recess. The elongate keeper plates have bearing surfaces that slidably contact the primary portion, including the primary bearing surface, of the slide and further have bearing surfaces that slidably contact the intermediate bearing surfaces of the slide. Surfaces of the first and second elongate keeper plates that contact surfaces, including the primary bearing surface, of the primary portion and that contact the intermediate bearing surfaces of the slide are softer than the primary portion and the intermediate bearing surfaces of the slide and are formed of self-lubricating material.

The keeper plates are attached to the cam adapter with fasteners such as bolts, and the assembled configuration reduces the likelihood of the bolts being loosened or damaged by minimizing the strength of forces applied to them during cam operation. The configuration of the keeper plates and the disposition of the bolts facilitates the removal and installation of the keeper plates without requiring cam removal from the press.

The rectangular recess of the cam adapter has a forward stop and a rear stop between which the primary portion of the slide is driven, and the slide also has a resilient member extending toward the forward stop. The resilient member is compressed against the forward stop as the primary portion of the slide is advanced, and the resilient member provides a slide-retracting force when the resilient member is allowed to decompress. The slide also has a shock absorber extending toward the rear stop of the rectangular recess to decelerate the slide as the slide nears a fully retracted position.

The driver has an elongate slot that extends along a portion of each side at the same angle to the horizontal as those of the driver bearing surface and the secondary bearing surface of the slide. A positive return member is secured to each side of the slide, and each positive return member has a projection that is slidably received by one of the elongate slots.

The driver bearing surface and the secondary bearing surface of the slide of the aerial cam each has an inverted V-shape that slidably conforms to the other. The driver bearing surface and the secondary bearing surface of the slide of the die-mount cam each has a V-shape that slidably conforms to the other.

The aerial and die-mount cams are basically inverted versions of each other. Efficiencies of assembly and installation and reduced expenses can be realized by using cam adapters, slides and drivers that have components that do not require custom fitting. The self-lubricating material on one of each pair of bearing and contacting surfaces extend the life of contacting surfaces that slide relative to one another.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

It should be noted that, when the term “cam” is used in this specification without particular reference to the type of cam, the term refers inclusively to aerial cams and die-mount cams. It should be further noted thatFIGS. 1,2,3and5do not show inner details of the cams.FIG. 4, however, is an exploded view that does reveal details of the inner structures.FIGS. 4 and 5show only one side of each cam represented, but the respective opposite sides and the components and features located there are mirror images of the components and features located on the sides shown.

FIG. 1is a perspective view of a front and first side of a representative narrow aerial cam, generally indicated by the reference numeral10, that includes a cam driving member, or cam adapter,12, a tool holding member, or slide,14, and a driver16. The cam adapter12is secured, typically by bolts13(FIG. 2) passing through bolt holes18, to an upper platen21(FIG. 2) of a press (not shown). To facilitate properly aligning the cam adapter12, the latter has a key20that is secured within a keyway22by a fastener such as a bolt24(FIG. 4). The key20is received within a mating keyway within the upper platen21(FIG. 2). The driver16is secured, by fasteners such as bolts13(FIG. 2) passing through bolt holes18, to a lower platen23(FIG. 2) of the press (not shown). Efficiencies of assembly and installation and reduced expenses can be realized by using cam adapters12, slides14and drivers16that have components that do not require custom fitting.

Also shown byFIG. 1are first sides,26,36and40of the cam adapter12, the slide14and the driver16respectively. A first elongate keeper plate30is attached to the first side26of the cam adapter12by fasteners such as bolts34. A V-block44, having an inverted-V-shaped driver bearing surface, generally indicated by the reference numeral46′ (FIG. 4), is secured atop the driver16by fasteners such as bolts48′ (FIG. 4), and slidably supports the slide14. The slide14has a front end84and a rear end86. A representative tool2is shown mounted on the front end84of the slide14with a representative tool holder4. The slide14has an inverted V-shaped secondary bearing surface, generally indicated by the reference numeral19′ (FIG. 4) that conforms to the driver bearing surface46′ of the V-block44′. The driver bearing surface46′ (FIG. 4) of the driver16upon which the slide14is slidably supported is inclined at an acute angle to the horizontal, and the driver16has a first elongate slot50that extends at the same acute angle to the horizontal. A first positive return member54(shown partially broken away) is secured within a first recess58to the first side36of the slide14by a fastener such as a bolt62. At an end distal from the bolt62securing the first positive return member54to the slide14, the first positive return member54has a generally rectangular first projection64(seeFIG. 3and the second projection66′,FIG. 4) that slidably extends into the first elongate slot50.

FIG. 2is a view of a second, opposite side of the narrow aerial cam10ofFIG. 1. The components and features located on the second side of the narrow aerial cam10are mirror images of those of the first side, and their functions are the same as previously described for their respective counterparts on the first side. Shown are second sides,28,38and42of the cam adapter12, the slide14and the driver16respectively. A second elongate keeper plate32is attached to the second side28of the cam adapter12. The driver16has a second elongate slot52, which is inclined at the same acute angle to the horizontal as that of the first elongate slot50ofFIG. 1. A second positive return member56is secured to the second side38of the slide14.

FIG. 3is a rear view of the narrow aerial cam10ofFIG. 2, shown partially in cross-section, taken on the line3-3ofFIG. 2. It shows the cam adapter12and the first and second elongate keeper plates30and32, in section, attached to the cam adapter12and also indicates respective first and second longitudinal slots68and70in the elongate keeper plates30and32. Also shown is a rear-end view of the slide14and first and second positive return members,54and56respectively, and respective first and second projections64and66extending respectively from the first and second positive return members54and56. Bolts34securing the first and second elongate keeper plates30and32to the cam adapter12are also represented. The assembled configuration reduces the likelihood of the bolts34being loosened or damaged by minimizing the strength of forces applied to them during cam operation. The configuration of the elongate keeper plates30and32and the disposition of the bolts34facilitates the removal and installation of the elongate keeper plates30and32without having to remove the cam10from the press (not shown).

Except for having a driver16′ with an uninclined driver bearing surface46′ rather than an inclined driver bearing surface as with the driver16(FIG. 2) and having a slide14′ with an uninclined secondary bearing surface19′ rather than an inclined secondary bearing surface as with the slide14(FIG. 2), a narrow aerial cam10′ shown byFIG. 4would be similar to an exploded, perspective view of the narrow aerial cam10ofFIG. 2. As mentioned previously,FIG. 4shows only one side of the aerial cam represented, but the opposite side and the components and features located there are a mirror image of the second side and the components and features located there. Shown byFIG. 4are second sides,28′,38′ and42′ of the cam adapter12′, the slide14′ and the driver16′ respectively. A first elongate keeper plate30′ is attached to the first side (not shown) of the cam adapter12′, and a second elongate keeper plate32′ is attached to the second side28′ of the cam adapter12′ by fasteners such as bolts34′.

A V-block44′, having an inverted-V-shaped driver bearing surface, generally indicated by the reference numeral46′, is secured atop the driver16′ by fasteners such as bolts48′, and slidably supports the slide14′. The driver bearing surface46′ of the V-block44′ upon which the slide14′ is slidably supported is softer than the secondary bearing surface19′ of the slide14′ and is preferably formed of self-lubricating material. The driver bearing surface46′ is uninclined to the horizontal, and the driver16′ has a second elongate slot52′ that is also uninclined to the horizontal. A second positive return member56′ is secured within a second recess60′ to the second side38′ of the slide14′ by a fastener such as a bolt62′. At an end distal from the bolt62′ securing the second positive return member56′ to the slide14′, the second positive return member56′ has a generally rectangular second projection66′ that slidably extends into the second elongate slot52′.

As revealed by the exploded view ofFIG. 4, the slide14′ includes an elongate primary portion, generally indicated by the reference numeral72′, having a generally T-shaped cross section that delineates first and second longitudinal slots,74′ and76′ respectively. The slide also includes a secondary portion, generally indicated by the reference numeral73′, which includes the secondary bearing surface19′ in slidable contact with the driver bearing surface46′ of the V-block. The slide14′ has a front end84′ and a rear end86′. Extending from the front end84′ of the elongate primary portion72′ of the driver14′ is a resilient member, preferably a gas spring,88′; and extending from the rear end86′ is a shock absorber90′. The cam adapter12′ has a rectangular recess, generally indicated by the reference numeral92′, that slidably receives the elongate primary portion72′ of the slide14′. One end of the rectangular recess92′ acts as a forward stop94′ against which the gas spring88′ is compressed when the slide14is advanced. The opposite end of the rectangular recess92′ acts as a rear stop96′ against which the shock absorber90′ is compressed when the slide14is retracted.

The mutually inwardly facing inner bearing surfaces of the first and second elongate keeper plates,30′ and32′ respectively, have first and second longitudinal slots68′ and70′ that slidably receive the generally rectangular elongate primary portion72′ of the slide14′. The configuration of the primary portion72′ and of the intermediate bearing surfaces78′ and80′ of the slide and their cooperation with the rectangular recess bearing surface of the cam adapter12′ and with the bearing surfaces of the elongate keeper plates30′ and32′ contribute to the increased load-bearing capacity of the cam and to an increased lateral and angular stability of the slide14′ of the cam. The slide14′ has three bearing surfaces that receive downward forces from the cam adapter12′ and the elongate keeper plates30′ and32′ when the cam adapter12′ is forced downwardly by the upper platen21of the press (not shown). The top of the elongate primary portion72′ forms an elongate primary bearing surface82′; and lower bearing surfaces of the first and second elongate slots74′ and76′ extend laterally to form first and second intermediate bearing surfaces,78′ and80′ respectively.

The elongate primary bearing surface82′ receives downward forces from upper edges of the first and second longitudinal slots68′ and70′ of the first and second elongate keeper plates30′ and32′. The first and second intermediate bearing surfaces78′ and80′ receive forces respectively from the first and second lower bearing surfaces98′ and100′ of the first and second elongate keeper plates30′ and32′.

As represented by portions shown byFIG. 4of the first elongate keeper plate30′, portions of the inner bearing surfaces, including the bearing surfaces of the first and second longitudinal slots68′ and70′, of the first and second elongate keeper plates30′ and32′ are formed of material that is softer than the bearing surfaces of the upper portion72′ of the slide14′ and are preferably formed of self-lubricating material. First and second lower bearing surfaces98′ and100′ of the first and second elongate keeper plates,30′ and32′ respectively (similar to the first and second upper bearing surfaces272and274shown byFIG. 5), have softer bearing surfaces than the respective first and second intermediate bearing surfaces78′ and80′ of the slide14′ and are preferably formed of self-lubricating material.

The bearing surfaces cooperatively extend continuously across the distance between opposite sides of the driver, slide and cam adapter, distributing loads across the entire width of the cam. Moreover, as shown best byFIG. 4, in the aerial cam shown, a portion of the elongate primary bearing surface82′ spacedly overlaps a portion of each of the first and second intermediate bearing surfaces78′ and80′, and it also spacedly overlaps a portion of the driver bearing surface46of the V-block44′. The first and second intermediate bearing surfaces78′ also spacedly overlap portions of the driver bearing surface46of the V-block44′. In the die-mount cam shown byFIG. 5, the secondary bearing surface219of the slide214spacedly overlaps portions of the first and second upper bearing surfaces272and274of the first and second elongate keeper plates,230and232respectively, and spacedly overlaps the bearing surface (not shown but similar to an inverted rectangular recess bearing surface93′ of the rectangular recess shown byFIG. 4).

The portions of bearing surfaces overlapped represent bearing surfaces in excess of those necessary to cooperatively extend continuously across the distance between opposite sides of the driver, slide and cam adapter; and they do so without adding to the overall width of the cam. These features facilitate the fabrication of cams that are narrower and whose slides have increased angular stability. The configuration provides the cams of the present invention with a load-bearing capacity of some 4 tons.

The narrow aerial cam10′ shown byFIG. 4will now be used as a representative example of the aerial cams shown byFIGS. 1,2,3and4in describing their operation. When the cam adapter12′ is pressed downwardly by the upper platen21(FIG. 2) of the press (not shown), an attending downward force is exerted upon the first and second elongate keeper plates30′ and32′ secured to the cam adapter12′. The first and second keeper plates30′ and32′ communicate the attending force to the inclined elongate primary bearing surface82′ of the slide14′ and to the likewise inclined intermediate bearing surfaces78′ and80′ of the slide14′. A component of the downward force exerted upon the inclined elongate primary bearing surface82′ and the inclined intermediate bearing surfaces78′ and80′ advances the slide14′ along the driver bearing surface46′ of the V-block44′. Due to the relative motions of the cam adapter12′ and the slide14′, as the cam adapter12′ is forced downwardly by the upper platen21of the press (not shown), the gas spring88′ is compressed against the forward stop94′ within the rectangular recess92′ of the cam adapter12′.

At an end distal from the bolt62′ securing the second positive return member56′ to the slide14′, the second positive return member56′ has a generally rectangular second projection66′ that slidably extends into the second elongate slot52′ of the driver16′. A first generally rectangular projection (not shown but a mirror image of the second projection66′) slidably extends from a first positive return member54′ into a first elongate slot (not shown but a mirror image of the second elongate slot52′) in the driver16′.

When the slide14′ is to be retracted, the cam adapter12′ shown byFIG. 4is forced upwardly by the platen21of the press (not shown). The generally rectangular elongate primary portion72′ of the slide14′, which is slidably contained within the rectangular recess92′ of the cam adapter12′ and the first and second longitudinal slots68′ and70′ of the first and second elongate keeper plates30′ and32′, is pulled upwardly. The inclined disposition of the bearing surfaces supporting the elongate primary portion72′ of the slide14′ within the rectangular recess92′ results in a component of the vertical force that is pulling the cam adapter12′ upwardly being directed laterally to retract the slide14′. The component force acting to retract the slide14′ is supplemented by a force provided by the gas spring88′ as it decompresses.

Likewise, with reference toFIGS. 1 and 2, when the cam adapter12is forced upwardly by the upper platen21of the press (not shown), the slide14is retracted by component forces applied to the slide14by the first and second elongate keeper plates30and32and by the decompressing gas spring88′ (FIG. 4). An upwardly directed component of the force applied to the slide14by the first and second elongate keeper plates30and32is also communicated to the first and second positive return members54and56, which are secured to the slide14. When the projections (see second projection66′ ofFIG. 4) extending from the first and second positive return members54and56are forced upwardly within the first and second, stationary, inclined, elongate slots50and52respectively, the positive return members54and56force the slide14to retract even if the forces applied to the slide14by the first and second elongate keeper plates30and32and by the decompressing gas spring88′ (FIG. 4) fail to do so. The first and second positive return members54and56also limit the separation of the slide14from the driver16.

FIG. 5is a perspective view of a narrow die-mount cam, generally indicated by the reference numeral210. It is essentially an inverted version the narrow aerial cam10shown byFIG. 1, shown from a different perspective. As mentioned previously,FIG. 5shows only one side of the cam represented, but the opposite side and the components and features located there are a mirror image of the respective components and features located on the side shown. The narrow die-mount cam210includes a cam driving member, or cam adapter,212, a tool holding member, or slide,214, and a driver216. The cam adapter212is secured, typically by bolts13(FIG. 2) passing through bolt holes218, to the lower platen23(FIG. 2) of the press (not shown). The driver216is secured, by fasteners such as bolts13(FIG. 2) passing through bolt holes218, to the upper platen21(FIG. 2) of the press (not shown).

Also shown byFIG. 5are second sides228,238and242of the cam adapter212, the slide214and the driver216respectively. A first elongate keeper plate230is attached to a first side (not shown but a mirror image of the second side228) of the cam adapter212; and a second elongate keeper plate232is attached to the second side228of the cam adapter212by fasteners such as bolts234. A V-block244, having a V-shaped driver bearing surface (see driver bearing surface46′,FIG. 4), is secured below the driver216, and is slidably supported by the slide214. The slide214has a V-shaped secondary bearing surface, generally indicated by the reference numeral219, that conforms to the driver bearing surface of the V-block244. The driver bearing surface of the driver216that is slidably supported by the slide214is inclined at an acute angle to the horizontal, and the driver216has a second elongate slot252that extends at the same acute angle to the horizontal. A second positive return member256is secured within a second recess260to the second side238of the slide214by a fastener such as a bolt262. At an end distal from the bolt262securing the second positive return member256to the slide214, the second positive return member256has a generally rectangular first projection (see second projection66′,FIG. 4) that slidably extends into the second elongate slot252.

The slide214is configured to support a tool holder204that is capable of holding any of a number of well-known tools such as a representative punch202shown. The cam adapter212, being on the bottom, slidably supports the slide214, which in turn slidably supports the driver216. The components and features of the opposite side of the narrow die-mount cam210shown byFIG. 5are mirror images of those of the side shown.

As described for elements of the cams shown by previous figures, similar respective bearing surfaces that are not exposed byFIG. 5are harder or softer relative to another upon which it slides. As described previously, the softer bearing surfaces, for example, first and second upper bearing surfaces,272and274respectively, of the first and second elongate keeper plates230and232are preferably formed of self-lubricating material.

The operation of the die-mount cam210is similar to that of the aerial cam10. As the driver216is forced downwardly by the upper platen21of the press (not shown) and the slide214advances along the cam adapter212, the tool202(FIG. 5) secured to the slide214by a tool holder204(FIG. 5) is advanced toward a workpiece (not shown). When the driver216is forced upwardly by the platen21of the press (not shown), the slide214and tool202are retracted. The advancement and retraction of the slide214are accomplished as described for slides shown by the previous figures.