GB2201727A

GB2201727A - Releasable retaining devices

Info

Publication number: GB2201727A
Application number: GB08805347A
Authority: GB
Inventors: Robert Mackean Agnew
Original assignee: METAL PLANT Ltd
Current assignee: METAL PLANT Ltd
Priority date: 1987-03-06
Filing date: 1988-03-07
Publication date: 1988-09-07
Anticipated expiration: 2008-03-07
Also published as: GB8805347D0; GB8705236D0; GB2201727B

Abstract

A readily releasable interconnection device for coupling first and second articles one to the other, includes a pin member (11) connected to the first article and a pin member locking unit (12) connected to the second article. The unit (12) includes a locking ball carrier (50) at least one through bore (57) within which a locking ball (58) is displaceable between locking and releasing positions, and a locking ball position control sleeve (59) for controlling the position of each locking ball (58) within its associated bore. The operational movement path of the ball(s) is so inclined relative to the direction of engagement/disengagement of the pin member (11) with the locking unit (12) that displacement of the pin member during a disengagement operation produces a force component which is able assists the ball(s) disengagement movements. <IMAGE>

Description

RELEASABLE RETAINING DEVICES This invention relates to devices for releasably interconnecting elements, units, or the like that are required to be readily separable one from the other.

In particular, but not exclusively, the present invention is concerned with an interconnection device for joining together the male and female sections of moulds utiliised for the production of mouldings of fibreglass by, for example, resin transfer moulding processes.

In resin transfer processes for the production of fibreglass mouldings it is frequently necessary to utilise relatively large moulds which comprise a bottom section and a top section which need to be separated one from the other, for the purposes of introducing the material to be moulded and for the subsequent removal of the moulded article from the mould, and which for the purposes of the actual moulding operation need to be firmly connected together so that the two mould sections are maintained in their correct relative positions to each other and so that it is also ensured that any pressures that may be produced in the mould during the moulding operation do not result in any relative displacements of the mould sections.

In addition, for the purposes of efficient production operations it is important that the connection between the two mould sections should enable the two mould sections to be easily and quickly separable from each other.

It is a usual resin transfer moulding production practice for upper mould sections to be bodily vertically displaceable towards and away from the lower section, and that any mould section interconnection sytem used should comprise a plurality of separate retaining/locking devices. A further requirement for any mould section interconnection system is that it should facilitate relative positional location of the two sections. In other words the interconnnection system needs to be able to accommodate during any relative movement between mould sections any slight tilting of the upper section relative to the lower section.

It is an object of the present invention to provide an improved readily releasable interconnection device which is particularly suitable for use in an interconnection system for cooperable mould seotions.

Broadly, according to the present invention there is provided a readily releasable interconnection device for coupling first and second elements one to the other, including a pin member adapted for operational connection to a first of the elements to be connected together, and a pin member locking unit adapted for operational connection of a second of the elements to be connected together, wherein the dthe unit includes a locking ball carrier member adapted for receiving at least one locking ball guide within which a ball is displaceable between locking and releasing positions, and a locking ball position control member for controlling the position of each ball wihin its associated ball guide, the arrangement being such that the operational movement path of the balls is so oriented with respect to the direction of engagement/disengagement of the pin member relative the locking unit that displacement of the pin member during a disengagement operation is arranged to produce a force component which is able so to act upon the balls as to assist their disengagement movements.

For a better understanding of the invention and to show how to carry the same into effect reference will be made to the accompanying drawings in which: Figure 1 is a very schematic cross sectional view of a fibreglass mould arrangement for a resin transfer moulding process, the Figure illustrating the general features thereof; Figure 2 is a cross sectional view of a first embodiment of a retaining/locking device incorporating the concepts of the invention; and Figure 3 is a two part cross sectional view to an enlarged scale of a second embodiment of a retaining/locking device incorporating the concepts of the invention, the left and right hand sides of the Figure 3 illustrating different operational positions of the device; Referring now to Figure 1 a mould unit is very schematically shown in cross section at 1 and incorporates a bottom section 2 and a top section 3.

The bottom section 2 includes a main body part 4 incorporating the article forming part 5 of the mould (i.e., the female part) and a peripheral flanged part 6.

The top section 3 similarly includes a main body part 7 incorporating the complementary moulding forming part 8 of the mould and a corresponding peripheral flange 9.

The sections 2 and 3 are held together for the purposes of moulding by a group of retaining devices 10 of the invention which are provided at the flanged parts 6 and 9. For mould sections with generally rectangular flange parts there can be, for example, four or six of the devices. In practice, the number of devices 10 will be determined by the overall dimensions of the mould sections and the moulding pressures to be expected during use.

The devices 10 of the invention each comprises two main parts, a lockable pin member 11 which is secured to one of the mould sections flanged parts and a combined pin member guide and locking unit 12, the latter being located and positioned on the other mould section flanged part in such position that when the two mould sections are operationally positioned one on the other the pin member 11 can engage with the unit 12.

In so far as the present application is concerned it will be presumed that the pin members are is mounted to the top mould section.

As may be seen from Figure 2 each pin member 11 is of a circular cross section with one end thereof adapted for attachment to the flange part of the top section so that the pin projects downwardly from this flange part towards the flange part of the bottom section when the mould sections are superimposed. The other end 13 i.e., the free end, of the pin member is chamfered as at 14. A circumferential groove 15 spaced from the chamfer 14 is formed in the pin member.

The combined sleeve guide and locking unit 12 includes a cylindrical ball cage 16 including a main section 17 and a section 18 of lesser diameter, the transition of diameters forming a transversely directed step 19.

The main section 17 has an internal bore 20 terminating at an internal transverse surface 21, whereby the section 18 has an annular wall 22 with inner and outer cylindrical surfaces 23 and 24. The bore 20 is dimensioned so that the free end 13 of the pin member 11 is slidably enterable into the bore 20. The open end of the bore is internally chamfered as at 25 so as to facilitate the engagement of the pin member end 1-3 within the bore 20.

A group of equiangularly spaced through bores 26 is provided in the wall 22 and are inclined downwardly towards the outer cylindrical surface 24. The longitudinal axes of the bores 26 are inclined at, for example, sixty degrees to the longitudinal axis of the ball cage 16. Each bore 26 receives a ball 27 whose diameter is greater than the axial length of the associated bore 26. In other words if a ball 27 is flush with the outer surface 24 of the wall 22 a part of the ball 27 projects inwardly of the internal surface 23 of the wall 22, and if a ball 27 is flush with the surface 23 a part of the ball 27 projects outwardly of the outer surface 24. The number of bores can be selected according to the intended application of the interconnectiond device. Thus for example, two, three, four or more can be prpvided.

A ball release and locking sleeve 28 is mounted upon the ball cage 16 so as to be smoothly lengthwise slidable on the surface 24 of the wall 22. The sleeve 28 includes a larger diameter section 29 and a smaller diameter section 30 the change in diameters forming a circumferential step 31. The smaller diameter section 30 terminates at an inwardly directed flange 32 adapted for engagement with the step 19 of the ball cage 16.

The internal cylindrical surface 33 of the sleeve 28 that is slidably to engage with the external surface 24 of the ball cage main section 17 has a larger diameter portion 34 which joins with the remainder of the surface by way of an outwardly flared-region 35.

This region of larger diameter 34 of the sleeve 28 produces an axially directed circumferential space 36 around the ball cage 16 into which the balls 27 can enter in order that they can move to their fully outermost positions as above considered.

The length of the space 36 is such that when the internally directed flange 32 abuts with the step 19 of the ball cage 16 the balls 27 will be located at their innermost positions. That is to say the formation of the space 36 is such that the flared region 35 is above (as related to the Figures as shown) the level which ensures that the balls are fully retracted.

When the position of the sleeve 28 with respect to the cage 16 is as shown in Figure 2 the balls 27 are in their fully inward positions (shown in full lines) and when the position of the sleeve 28 with respect to the cage is such that the outer ends of the ball bores are in the vicinity of the space 36 the balls 27 are able to move into their fully outermost positions (shown in dashed lines).

The sleeve 28 is resiliently loaded towards the position shown in Figure 2 by a spring 37 which abuts at one end against the step 19 and at its other end against a spring locating plate 38 held in place by a circlip 39 which engages with a associated groove or grooves 40 provided in the cage 16.

The lowermost end of the ball cage is provided with a threaded bore 41 for attachment to the rod or the like 42 of a double acting hydraulic or pneumatic jack 43 which is firmly connected with a base plate 44 by way of a retaining ring or plate 45.

The above discussed ball cage and sleeve assembly is housed within a tubular housing 46 having an internal surface 47 within which the sleeve 28 is a smooth or loose slidable fit. The housing 46 is conveniently held in place by one end 47 thereof by being secured to the retaining ring or plate 45. The housing 46 is open at its other end 48 to allow engagement of the pin member 11 with the ball cage bore. The end 48 has an internally directed preipheral flange 49 of such internal diameter as to be engageable by the upper end of the sleeve 28 but not by the upper end of the ball cage 16.

The mounting of the unit 12 to the mould flange 6 or 9 can be such that the housing upper end 48 is flush with the surface of the associated flange or so that the unit 16 is upstanding from the associated flange.

The operation of the device of figure 2 will now be considered. It will be assumed that initially the pin member 11 is not engaged within the ball cage 16 and that the jack rod 42 is at the lowest point of its predetermined travel.

In this position the resilient loading of the spring 37 will maintain the sleeve in the position shown in the Figure 2.

On operation of the jack unit 43 the ball cage 16 and the sleeve 28 will be moved simultaneously towards the open end 48 of the housing 46, until a position will be reached at which the upper end of the sleeve 28 will abut with the inwardly directed flange 49 of the housing 46 thereby arresting further upward movement of the sleeve 28. However, further upward movement of the jack rod will move the ball cage 16 upwards relative to the sleeve 28 thereby bringing the outer ends of the ball cage bores 26 into the region of the space 36. At this position the balls 27 are able freely to roll downwards from their innermost positions towards their outermost positions and partially in the space 36. The length of the upward stroke of the jack rod 42 is arranged to produce this relative displacement without moving the balls to a level at which they could roll out from the cage 16.

This relative setting of the sleeve 28 and ball cage 16 can be regarded as the ready to receive the pin setting.

It will now be presumed that it is required to engage the pin member 11 with the unit 12. To do this the upper mould section 3 is lowered towards the lower mould section 2 such that the associated pin member free end 13 enters into the ball cage bore 20, the chamfering of both the pin member and the bore facilitating this engagement. On further lowering of the mould section the pin member 11 is pushed deeper into the ball cage bore 20 and in so doing the chamfer 14 on the free end 13 of the pin member will push the balls 27 fully out of the path of the pin member 11.The relative dimensions of all of the components involved i.e., the pin member 11, the unit 12, the mould sections 2,3 etc., are such that by the time the upper mould section 3 has located with and engaged with the bottom mould section 2 the associated pin members 11 will have been moved to a position relative to their associated ball cages 16 such that the grooves 1.5 therein have been positioned so that the balls 27 are able to move into engagement position with the grooves. This position can be regarded as the upper mould section located setting.

After this setting has been attained it is necessary to lock the upper mould section to the lower section so that the moulding pressures can be accommodated without any relative displacements of the mould. This locking is effected by exerting downward pull onto the pin members 11 thereby pulling the upper mould section into tighter engagement with the lower mould section. That is to say into a mould locked setting.

This is achieved for each pin member 11 and associated unit 12 as follows. The jack unit 43 is operated to pull the ball cage 16 downwards. During the initial stage of this downward movement as a result of the spring loading on the sleeve 28 the sleeve remains in its uppermost position so that the ball cage 16 is moved downwards relative to the sleeve 28. This relative movement effectively moves the ball bores 26 from the region of the space 36 towards the smaller diameter bore of the sleeve 28 and in so doing progressively pushes the balls 27 inwardly whereby the balls are moved into engagement with the groove in the pin member 11. From this point onwards further downward movement of the cage will move the balls downwards relative to the pin member groove 15 until the balls cooperate with the bottom of the groove. After such co-operation any further downward movement of the jack rod 42 will exert a downward pull upon the pin member 11. It is arranged that by the time the balls 27 engage with the pin member groove the step 19 in the ball cage 16 will abut with the internally directed flange 32 of the sleeve to thereafter constrain the sleeve 28 to move downwards with the ball cage 16. It will thus be noted that at this point the pin member 11, the ball cage 16 and the sleeve 28 are being simultaneously pulled downwardly.

The downward stroke of the jack rod 42 is set to ensure that when it has reached the end of its predefined downward stroke the associated pin member 11 has been pulled sufficiently downwards to ensure that the pull exerted upon the pin member 11 will hold the associated upper mould section 3 in its correct moulding position with respect to the bottom mould section 2.

When, at the end of the moulding operation it is required to open the mould it is necessary to release not only the locking action produced by the pin member engaging and locking unit 12 but also an additional sealing effect produced by the actual moulding operation (this can be conveniently regarded as an additional or extra locking force) which force has to be removed in order to release the top section from the bottom section.

The removal of the mould top section is achieved as follows: The jack unit 43 is re-actuated to move the jack rod 42 upwards. The first part of the upward movement exerts upward push upon the pin member 11 by the engagement of the transverse surface 21 of the ball cage bore pressing against the bottom of the pin member 11.

Following this engagement upward movement of the jack rod 42 pushes against the pin member and in so doing breaks said extra sealing or locking force between the top and bottom mould sections. During this phase of the mould release operation any relative movement that may be required between the ball cage 16 and the pin member 11 is accommodated by effective upward displacement of the groove 15 in the pin member 11 relative to the balls 27. That is to say the balls 27 are not subjected to excessive vertical forces or stresses during this particular operation. The releasing operation is completed by further movement of the jack rod 42 moving the sleeve 28 into engagement with the inwardly directed flange 49 of the housing 46 whereupon the above previously discussed sequence of events occurs which allows the balls 27 to move outwardly down the ball bores 26.

At this point the pin members 11 are effectively fully released so that the upper mould section 3 can be lifted away from the bottom section 2. The upward removal of the pin members 11 will automatically displace the balls 26 to their release positions. This movement is ensured by an outwardly directed component of force being exerted upon the balls 27 by reason of the outwardly downward inclination of the ball bores 26, during of the displacement of the lower surface of the pin groove past the inner ends of the ball bores 26.

This arrangement ensures that the pin member is automatically released by the upward stroke of the jack rod 42.

The second embodiment of the device 12 i.e., that of Figure 3 differs from that of Figure 2 in that it is of a considerably simpler construction and involves fewer components.

The second embodiment incorporates a ball cage 50 having an internal bore 51 terminating at a transverse base surface 52 and defining a annular wall 53 with inner and outer cylindrical surfaces 54,55 respectively.

The bore 51 is dimensioned so that the free end 13 of the pin member 11 is slidably enterable into the bore 51. The open end of the bore is internally chamfered as at 56 so as to facilitate the engagement of the pin member end 13 within the bore 51.

A group of through bores 57 is provided in the wall 53. The bores 57 are equiangularly spaced around the wall 53 and are inclined downwardly towards the outer cylindrical surface 25 of the ball cage 50. The longitudinal axes of the bores 57 are inclined at sixty degrees to the longitudinal axis of the ball cage 50.

The bores 57 are intended each to receive a ball 58 whose diameter is greater than the axial length of the associated bore 57. In other words if a ball 58 is flush with the outer surface 55 of the cage a part of the ball 58 projects inwardly of the internal surface 54 of the wall 53, and if a ball 58 is flush with the surface 54 a part of the ball 58 projects outwardly of the outer surface 55 of the wall 53.

This projecting part is intended to cooperate with the circumferential ball receiving groove 15 provided on the pin 11. The groove 15 is elongate and has upper and lower regions 15A and 15B which are profiled so as to enable linear/areal engagement between the balls and the end regions 15A and 15B rather than a point contact.

The operational positions of the balls are controlled by a ball release and locking sleeve 59 having an internal cylindrical surface 60 such that the sleeve 59 and ball cage 50 are capable of smooth slidable movement relative to each other by engagement of the ball cage external surface with the internal surface of the sleeve.

The internal cylindrical surface 60 of the sleeve 59 has a larger diameter portion 61 which joins with the remainder of the surface by way of an outwardly flared region 62.

This portion of larger diameter produces an axially directed circumferential space 63 around the ball cage 50 into which the balls 58 can enter in order that they can move to their fully outermost positions as above considered.

The axial length of the space 63 is such that when relative positions of the ball cage 50 and the sleeve are as shown in the left hand side of Figure 3 the balls will be located at their innermost positions. That is to say the formation of the space 63 is such that when the flared region 62 is as shown in the Figure 3 left hand side it is ensured that the balls are fully retracted.

When the relative position of the sleeve 59 with respect to the cage 50 is as shown in the right hand side of Figure 3, the balls 58 are in their fully inward positions (shown in full lines). When the sleeve is in this relative position with respect to the cage 50 the outer ends of the ball bores 57 are in the vicinity of the space 63, the balls 58 are able to move into their fully outermost positions (shown in full lines at the right hand side of Figure 3 and in dashed lines at the left hand side of Figure 3 dashed lines).

It will be noted that the upper part 57A of each one of the bores 57 has a part spherical shape that is complementary to the associated ball 58. In addition, the upper and lower ends 15A and 15B of the groove 15 are likewise shaped so as to have a shape complementary to that of the balls 58 so as to avoid a point contact between the ends 15A and 15B of the balls 58.

The sleeve is effectively positionally fixed by being either secured to a base plate i.e., the associated mould flange or to the cylinder of the jack unit, which latter is in turn effectively fixedly secured to the mould flange directly or indirectly (not shown).

The operation of the second embodiment will now be considered. It will be understood that during the operation of this second embodiment the requisite axial relative displacement between the sleeve 59 and the ball carrier cage 50 is produced by axial displacement of the ball cage upon actuation of the cylinder 66 to move its rod 65. The sleeve does not move.

In general the operational procedures and sequences required in securing the mould sections together and for effecting their release are generally similar to those involved with of Figure 2.

Thus to effect the mould locking operation after the sections have been'placed one upon the other and the pins 11 engaged in their respective bores 51 of the units 12 the ram rod 65 is moved downwardly thereby to pull the cage 50 downwards to such extent that the balls 58 are initially moved inwards by a rolling action into the lower end of the pin groove to their engagement position and then brought into firm contact with the upper end 15A of the pin groove 15. After this further pull down of the pin with tighten the join between the mould sections 2 and 3.

To effect the release of the pins the cylinder 66 is actuated to move the rod 65 upwards thereby to bring the space 63 into the vicinity of the outer ends of the ball bores 57. It will be appreciated that during the initial stages of the upward cylinder rod movement the bottom 52 of the sleeve bore 51 will push against the end 13 of the pin 11 thereby effecting the initial release of the locking together of the mould sections.

At the same time the pin groove 15 will start to move upwards with the sleeve. The relative displacement between the sleeve and the ball cage will bring the outer ends of the ball bores 57 into the vicinity of the space 63 to allow outward movement of the balls 58. As a consequence of the inclination of the bores in conjunction with the direction of the pushing forces exerted upon the ram rod 65 there is produced a component of force on each ball 58 in the axial direction of each bore which so acts upon the ball 58 therein as to cause automatic displacement of the ball towards the pin release position.A consequence of the action of this force component is to ensure that as soon as the space 63 is effectively moved to the position shown in the right hand side of Figure 3 the balls will be in their fully outmost positions and thus clear of the pin groove 15 thereby allowing free removal of the pin 11 from the bore 51 during a subsequent lifting of the upper section from the lower mould section.

Whilst the above discussion has centred around the use of balls as the locking elements it is to understood that rollers could be adopted if considered suitable for an intended construction of the releasable interconnection device.

It will be appreciated that whilst the forgoing general description has been concerned with the application of the device of the invention to the joining together of moulds associated with resin transfer processes for the production of fibre glass bodies the devices of the invention may be utilised in any situation in which it is required to connect firmly together two articles, bodies, elements or the like whilst providing for a quick/easy release function.

Claims

1. A readily releasable interconnection device for coupling first and second articles one to the other, including a pin member addpted for operational connection to a first of the articles to be connected together, and a pin member locking unit adapted for operational connection to a second of the articles to be connected together, wherein the unit includes a locking element carrier member adapted for receiving at least one locking element guide within which a locking element is displaceable between locking and releasing positions, and a locking element position control member for controlling the position of each locking element within its associated locking element guide, the arrangement being such that the operational movement path of the locking elements is so oriented with respect to the direction of engagement/disengagement of the pin member relative the locking unit that displacement of the pin member during a disengagement operation is arranged to produce a force component which is able so to act upon the locking elements as to assist their disengagement movements.

2. A readily releasable device as claimed in claim 1, wherein the locking element carrier member includes a cylindrical first sleeve provided with equiangularly spaced through bores in the wall thereof the bores being positioned such that the centres of the axial lengths of the bores lie in a common transverse plane of the sleeve wall, and wherein the locking element position control member comprises a second sleeve coaxially surrounding the first sleeve, the arrangement being such that relative displacement between the sleeves is utilised to control the operational settings of the locking elements in the associated bores.

3. A readily releasable device as claimed in claim 1 or 2, wherein the second sleeve is resiliently loaded towards the position that retains the locking elements in their pin member locking positions within the locking element carrier member.

4. A readily releasable device as claimed in claim 1 ,2 or 3,. wherein the pin member is provided with an axially elongate circumferential groove with which the locking elements are intended operationally to cooperate, and wherein the end walls of the groove are shaped as to be complementary to the shape of the locking elements thereby to present to the latter a linear/areal surface rather than a surface presenting point contact to the associated locking element.

5. A readily releasable device as claimed in claim 2,3 or 4, and wherein bores provided for the locking elements in the locking element carrier member are shaped at the end regions thereof so as to be complementary to the shape of the locking elements, the arrangement being such to present to the locking elements a linear/areal surface.

6. A readily releasable device as claimed in claim 2,3,4 or 5, and wherein the pin member is adapted automatically to displace the locking elements with respect to their associated bores during a pin member locking unit engagement operation, and wherein the engagement operation is also arranged automatically to displace the sleeves relative to each other thereby to allow the locking elements to move to their locking positon during such engagement operation.

7. A readily releasable device as claimed in claim 6, wherein following the attainment of the locked position between the pin member and the locking unit, the pin member can be so additionally displaced in the locking movement direction thereof that additional cramping or like force can be exerted between the articles being connected.

8. A readily releasable device as claimed in claim 7, wherein when it is required to release the pin member from the locking unit, an initial displacement of the pin member in the releasing direction is arranged to be effected prior to releasing displacemnt of the locking elements, the arrangement being such that the locking elements are not subjected to excessive force that may be required to separate the first and second articles following their interconnection.

9. A readily releasable device as claimed in claim 8, wherein said initial displacement is effected by exerting pressure directly upon the pin member, and wherein the pin member is arranged to be displaceable with respect to the first sleeve and the locking elements whilst in their locking setting without exerting releasing force on the locking elements.

10. A readily releasable device as claimed in any one of the claims 4 to 9, wherein the locking element position control member is operationally connected for displacement by the ram rod of a ram means mounted to the second of said articles.

11. A readily releasable interconnection means, constructed and arranged to operate substantially as hereinbefore described with refgertence to Figures 1 and 2 or Figures 1 and 3 of the accompanying drawings.