GB2294518A - Cam device for obtaining backlash-free movement - Google Patents
Cam device for obtaining backlash-free movement Download PDFInfo
- Publication number
- GB2294518A GB2294518A GB9421815A GB9421815A GB2294518A GB 2294518 A GB2294518 A GB 2294518A GB 9421815 A GB9421815 A GB 9421815A GB 9421815 A GB9421815 A GB 9421815A GB 2294518 A GB2294518 A GB 2294518A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cam
- rolls
- spindle
- operating member
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B9/00—Blowing glass; Production of hollow glass articles
- C03B9/13—Blowing glass; Production of hollow glass articles in gob feeder machines
- C03B9/14—Blowing glass; Production of hollow glass articles in gob feeder machines in "blow" machines or in "blow-and-blow" machines
- C03B9/16—Blowing glass; Production of hollow glass articles in gob feeder machines in "blow" machines or in "blow-and-blow" machines in machines with turn-over moulds
- C03B9/165—Details of such machines, e.g. guide funnels, turn-over mechanisms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/08—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for interconverting rotary motion and reciprocating motion
- F16H25/12—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for interconverting rotary motion and reciprocating motion with reciprocation along the axis of rotation, e.g. gearings with helical grooves and automatic reversal or cams
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H53/00—Cams ; Non-rotary cams; or cam-followers, e.g. rollers for gearing mechanisms
- F16H53/06—Cam-followers
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Transmission Devices (AREA)
Abstract
A cam track 16 has opposed walls 18, 20 engaged by a roller follower assembly mounted on a spindle 32. The roller assembly has two coaxial rollers 26, 30 in engagement with wall 18 and a roller 28, mounted on an eccentric bearing portion of spindle 32, in engagement with wall 20. The spindle can be rotated to adjust the assembly to minimise backlash by taking up any clearance between the rollers and the walls. The adjustment can be manual or by a constant spring bias imparted to the spindle (Fig. 4). The device may be used to move an operating head in a glassware forming machine. <IMAGE>
Description
DEVICE FOR OBTAINING BACK LASH FREE MOVEMENT
This invention is concerned with a device for obtaining back lash free movement, in particular for use in moving mechanisms for use in a glassware forming machine for moving an operative member such as a blowhead, funnel or a baffle.
In a glassware forming machine of the so-called 'individual section' type, the need arises to move certain operative members between out of the way positions and operative positions in which the operative member is aligned with an opening of a mould cavity of the machine. For example the machine comprises a blank mould in which parisons are formed and it is necessary to move a funnel into alignment with the mould opening so that it can guide a gob of molten glass into the mould cavity and then into an out of the way position to allow a baffle to be positioned on the mould. The same situation arises with regard to the baffle in relation to the blank mould and with regard to a blowhead in relation to a blow mould in which the parisons formed in the blank mould are blown into containers by air supplied through the blowhead.
Conventional moving mechanism for moving such an operative member in an individual section type machine comprises a piston and cylinder assembly having a vertically extending piston rod which projects in both directions from a piston. One end portion of the piston rod carries a horizontally extending arm on which the operative member is mounted. The other end of the piston rod carries a cam roll which is engaged in a spiral cam track. The arrangement is such that, when the piston and cylinder assembly is operated, the piston rod moves vertically causing the operative member to move vertically. As this movement takes place the cam track causes the piston rod to turn about its longitudinal axis thereby swinging the arm and the operative member about the axis.The operative member is thus moved in a movement which has a rotary component about the longitudinal axis of the rod and a linear component in a vertical direction.
Moving mechanisms of the above type are shown for example in US 3,630,709, US 3,986,858 and US 4,120,683.
Available moving mechanisms of the above type suffer from certain disadvantages. It will be clear that it is important that the moving mechanism operates to position the operative member, whether it be a funnel, blowhead or baffle accurately with respect to the mould cavity when the operative member is in its operative position. Consequently it is desirable to ensure that any mis-positioning because of wear in the mechanism is minimized. Conventional moving mechanism of the type first described tend to suffer from wear problems giving rise to back lash in the movement resulting in mispositioning or vibration of the operative member. These may arise because, particularly in certain parts of the movement, there is a high stress (and consequently a tendency to wear) between the spiral cam track and the cam roll which leads to wear particularly at such parts of movement.Further, the roll normally contacts one side of the cam track on movement in one direction and the other side on movement in the other direction, giving a tendency to a small uncontrolled movement at the beginning of each change of direction in the swinging movement.
It is one of the objects of the present invention to provide a mechanism of the above mentioned type which is substantially free from back lash and not readily subject to deterioration from wear.
The present invention provides, as one of its features a device for obtaining back lash free movement of an operating member by use of a cam assembly comprising
a cam member comprising a cam track provided by two
opposed cam surfaces spaced apart by a substantially
constant distance,
a cam roller assembly mounted on the operating member
and arranged to run in the cam track,
means for causing relative movement of the cam track
and the cam roller assembly thus to obtain movement of
the operating member, the cam roller assembly being
urged against a first one of the cam surfaces when
relative movement takes place in one sense, and against
a second one of the cam surfaces when relative movement
takes place in the other sense,
characterized in that
the cam roller assembly comprises three or more cam
rolls mounted on a cam spindle secured to the operating
member and arranged transverse to the direction of
relative movement,
the cam rolls comprising a first set of at least two
cam rolls and a second set interposed between the cam
rolls of the first set
and the cam spindle comprises a first series of
concentric bearing surfaces which support the cam rolls
of the first set, and an interposed second series of
concentric bearing surfaces, eccentric to the first
series, which support the cam rolls of the second set.
Preferably in a device according to the invention the first set of rolls comprises two cam rolls and the second set of rolls comprises one roll interposed between two cam rolls of the first set. Such a device may comprise means for clamping the cam spindle in the operating member, which means is releasable to allow the cam spindle to be adjusted by rotation about its axis. Alternatively, the cam spindle may be mounted in the operating member so that it is capable of rotation about its axis, and means is provided to urge the spindle to rotate about said axis. Such means may be provided by a cut away portion on the spindle and spring means which urges a plunger against the cut away portion thus to urge the spindle about its axis.
The present invention also provides a moving mechanism for use in moving an operating head such as a baffle, funnel blow head or the like, in a glassware forming machine comprising a device as set out above wherein the operating head is supported on the operating member.
In the accompanying drawings
Figure 1 shows diagrammatically a conventional moving mechanism for use in moving a blow head in a glassware forming machine
Figure 2 shows a plan view of first cam assembly embodying the invention for use in a mechanism as shown in
Figure 1.
Figure 3 shows a side view, partly broken away, of a second cam assembly embodying the invention.
Figure 4 shows a view partly broken away, in the direction of the arrow IV in Figure 3.
The conventional moving mechanism shown in Figure 1 is for moving an operating head in the form of a blow head 2, but it will be understood that a similar mechanism can be utilized for other operating heads, for example a baffle or a funnel.
The moving mechanism comprises a piston and cylinder assembly, of which the piston 4 only is shown, and a vertically extending operating member in the form of a piston rod 6 which projects in both directions from the piston 4. One end portion 8 of the piston rod 6 carries a horizontally extending arm 10 on which the blow head 2 is mounted. The other end 12 of the piston rod 6 carries a cam roll 14 which is engaged in a spiral cam track 16 which is provided by two opposed cam surfaces 18, 20 which are spaced apart by a substantially constant distance. The piston and cylinder device provides means for causing relative movement of the cam track 16 and the cam roll 14, and the arrangement is such that when the piston and cylinder device is operated, the piston rod 6 moves vertically, causing the blow head 2 to move vertically. As this movement takes place, the cam track 16 causes the piston rod 6 to turn about its longitudinal axis, thereby swinging the arm 10 and the blow head 2 about this axis. The blow head 2 is thus moved in a movement which has a rotary component about the longitudinal axis of the rod 6 and a linear component in a vertical direction.
The moving mechanism shown in Figure 1 suffers from a major disadvantage. It will be realized that, because of the load on the piston rod 6, on downward movement of the cam roll 14 in the cam track 16, the roll 14 will be urged into engagement with the cam surface 20, and equally on upward movement of the roll 14 it will be urged into engagement with the cam surface 18. To avoid jerky movement of the piston rod 6, and thus of the blow head 2, when manufacturing such a mechanism as little play as possible is allowed between the cam roll 14 and the cam track 16, which contributes significantly to the cost of manufacture.
Further, during operation of the mechanism wear takes place, both of the cam roll 14 and of the cam surfaces 18 and 20.
Thus increases the amount of jerky movement of the blow head 2 and eventually requires repair or replacement of the mechanism.
Figure 2 shows a first cam assembly which can be used to provide a device embodying the invention when incorporated in a mechanism as first described.
Figure 2 shows, diagrammatically, the cam surfaces 18 and 20 of the cam track 16, and a cam roller assembly 24 mounted on the piston rod 6 in substitution for the cam roll 14.
The cam roller assembly 24 comprises three cam rolls 26, 28, 30, mounted on a cam spindle 32 which is secured to the piston rod 6 and arranged transversely to the direction of relative movement between the cam track 16 and the piston rod 6. The rolls 26, 30 provide a first set of cam rolls, and the cam roll 28 provides second set of cam rolls, being interposed between the rolls 26 and 30.
The cam spindle 32 comprises a conical portion 34 which fits into a conical bore 36 of the piston rod 6, and a threaded end portion 38 carrying a nut 40 which, on tightening, locks the spindle 32 in radial position in the piston rod 6.
The cam spindle 32 comprises a first series of concentric bearing surfaces 42, 44 which are concentric with the axis of the spindle 32: the cam roll 26 is mounted on the surface 42 and the cam roll 30 on the surface 44.
Interposed between the surfaces 42 and 44 is a second bearing surface 46 which is eccentric to the surfaces 42 and 44 and to the axis of the spindle 32. The cam roll 28 is supported on the surface 46. A nut 48 on an end portion of the spindle 32 holds the cam rolls 26, 28, 30 on their bearing surfaces . Friction reducing spacers 50, 52 are positioned between the adjacent cam rolls.
It can be seen that, on setting up the mechanisms, the nut 40 may be slackened to allow the spindle 32 to be rotated to bring the rolls 26 and 30 into contact with the cam surface 18 and the roll 28 into contact with the cam surface 20. Thus, when the moving mechanism operates, on downward movement of the piston rod 6 the cam surface 20 acts on the cam roll 28 to obtain rotational movement of the rod 6, and on upward movement of the rod 6, the cam surface 18 acts on the cam rolls 26 and 30 to obtain rotational movement of the rod 6. There is no slack to be taken up when the piston rod 6 changes from downward to upward movement.Not only does this arrangement facilitate setting up the moving mechanism, but it greatly reduces wear of the cam rolls and the cam track and, even if such wear occurs it can be allowed for by rotation of the spindle 32 to bring both sets of rolls in contact with both surfaces of the cam track 16.
The mechanism described utilizes a first set of cam rolls comprising two rolls and a second set comprising only one interposed between the two. It will be understood that more rolls may be utilized if desired, though a larger number will tend to be expensive. We have found it desirable to ensure that the endmost rolls are both members of the same set of rolls as this reduces any tendency for there to be unbalanced forces on the piston rod 6.
Figures 3 and 4 show a second cam assembly which can be used to provide a device embodying the invention when incorporated in a mechanism as described with reference to
Figure 1.
Figure 3 and 4 show, diagrammatically the cam surfaces 18 and 20 of the cam track 16 and a cam roller assembly 60 mounted on the piston rod 6 in substitution for the cam roll 14.
The cam roller assembly 60 comprises three cam rolls 62, 64, 66 mounted on a cam spindle 68 which is secured to the piston rod 6 and arranged transversely to the direction of relative movement between the cam track 16 and the piston rod 6. The rolls 62, 66 provide a first set of cam rolls, and the cam roll 64 provides a second set of cam rolls, being interposed between the rolls 62, 66.
The cam spindle 68 is rotatably mounted in a bore 70 of the piston rod 6. A segment of the spindle 68 is cut away at 72, providing a flat chordal surface 74. Threaded into an axial bore 76 of the rod 6 is a plug 78 which supports an axial cylindrical block 80. Slidably mounted around the block 80 is a cylindrical plunger 84 which fits into a bore 86 in the rod 6. A head 88 on the plunger 84 is slidably mounted in a bore 90, and a spring 92 acting between the block 80 and the plunges 84 urges a flat upper surface 94 of the head 88 into contact with the flat chordal surface 74.
The head 88 fits closely into the cutaway segment 72 and thus restrains the spindle 68 against axial movement.
It can be seen, from Figure 4, that the action of the spring 92 is to urge the spindle 70 in an anticlockwise direction [viewing Figure 4].
The spindle 68 comprises a first series of concentric bearing surfaces 96, 98 which are concentric with the axis of the spindle 68: the cam roll 62 is mounted on the surface 96 by means of a bearing 100, and the cam roll 66 is mounted on the surface 98 by means of a bearing 102.
Interposed between the surfaces 96 and 98 is a second bearing surface 104 which is eccentric to the surfaces 96 and 98 and to the axis of the spindle 68. The cam roll 64 is supported by means of a bearing 106 on the bearing surface 104 Friction reducing spacers 108, 110 are positioned between the adjacent cam rolls and a further spacer 112 between the cam roll 66 and the piston rod 6.
The cam roller assembly 60 is held on the spindle 68 by a washer 112 secured by a nut 114 threaded onto an end portion of the spindle 68.
It can be seen that the action of the spring 92 in urging rotation of the spindle 68 is to urge the cam roll 64 into contact with the cam surface 20 and the cam rolls 62 and 66 into contact with the cam surface 18. Thus this arrangement not only ensures that the cam rolls are in contact with the opposed cam surfaces at all times, but also operates automatically to compensate for any wear which may take place or the cam rolls or the cam tracks.
Claims (6)
1. A device for obtaining back lash free movement of an operating member by use of a cam assembly comprising
a cam member comprising a cam track provided by two
opposed cam surfaces spaced apart by a substantially
constant distance
a cam roller assembly mounted on the operating member
and arranged to run in the cam track,
means for causing relative movement of the cam track
and the cam roller assembly thus to obtain movement of
the operating member, the cam roller assembly being
urged against a first one of the cam surfaces when
relative movement takes place in one sense, and against
a second one of the cam surfaces when relative movement
takes place in the other sense,
characterized in that
the cam roller assembly comprises three or more cam
rolls mounted on a cam spindle secured to the operating
member and arranged transverse to the direction of
relative movement,
the cam rolls comprising a first set of at least two
cam rolls and a second set interposed between the am
rolls of the first set
and the cam spindle comprises a first series of
concentric bearing surfaces which support the cam rolls
of the first set, and an interposed second series of
concentric bearing surfaces, eccentric to the first
series, which support the cam rolls of the second set.
2. A device according to claim 1 wherein the first set of rolls comprises two cam rolls and the second set of rolls comprises one roll interposed between the cam rolls of the first set.
3. A device according to one of claims 1 and 2 comprising means for clamping the cam spindle in the operating member, which means is releasable to allow the cam spindle to be adjusted by rotation about its axis.
4. A device according to one of claims 1 and 2 wherein the cam spindle is mounted in the operating member so that it is capable of rotation about its axis, and means is provided to urge the spindle to rotate about said axis.
5. A device according to claim 4 wherein the spindle is provided with a cut away portion, and spring means mounted in the operating member urges a plunger against the cut away portion thus to urge the spindle about its axis.
6. A moving mechanism for use in moving an operating head, such as a baffle, funnel, blow head or the like, in a glassware forming machine comprising a device according to any one of the preceding claims wherein the operating head is supported on the operating member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9421815A GB2294518A (en) | 1994-10-29 | 1994-10-29 | Cam device for obtaining backlash-free movement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9421815A GB2294518A (en) | 1994-10-29 | 1994-10-29 | Cam device for obtaining backlash-free movement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9421815D0 GB9421815D0 (en) | 1994-12-14 |
| GB2294518A true GB2294518A (en) | 1996-05-01 |
Family
ID=10763589
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9421815A Withdrawn GB2294518A (en) | 1994-10-29 | 1994-10-29 | Cam device for obtaining backlash-free movement |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2294518A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0919473A1 (en) * | 1997-11-30 | 1999-06-02 | Poly-clip System GmbH & Co. KG | Device for closing tube-like or bag-like package envelopes |
| FR2821912A1 (en) * | 2001-03-06 | 2002-09-13 | Ina Schaeffler Kg | GROOVE CAM MECHANISM |
| FR2821911A1 (en) * | 2001-03-06 | 2002-09-13 | Ina Schaeffler Kg | GROOVE CAM MECHANISM |
| WO2009090749A1 (en) * | 2008-01-18 | 2009-07-23 | Toyo Glass Machinery Co., Ltd. | Baffle, funnel, or blow head driving device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3937102A (en) * | 1974-07-22 | 1976-02-10 | Allen Clayton H | Noise suppression |
| GB1458779A (en) * | 1974-07-05 | 1976-12-15 | Warnke Umformtech Veb K | Transport system with cam-controlled drive for presses |
| GB2168124A (en) * | 1984-11-30 | 1986-06-11 | Pilkington Perkin Elmer Ltd | Improvements in or relating to cam mechanisms |
-
1994
- 1994-10-29 GB GB9421815A patent/GB2294518A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1458779A (en) * | 1974-07-05 | 1976-12-15 | Warnke Umformtech Veb K | Transport system with cam-controlled drive for presses |
| US3937102A (en) * | 1974-07-22 | 1976-02-10 | Allen Clayton H | Noise suppression |
| GB2168124A (en) * | 1984-11-30 | 1986-06-11 | Pilkington Perkin Elmer Ltd | Improvements in or relating to cam mechanisms |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0919473A1 (en) * | 1997-11-30 | 1999-06-02 | Poly-clip System GmbH & Co. KG | Device for closing tube-like or bag-like package envelopes |
| US6182734B1 (en) | 1997-11-30 | 2001-02-06 | Poly-Clip System Gmbh & Co. Kg | Apparatus for sealing tubular or bag-shaped packaging casings |
| FR2821912A1 (en) * | 2001-03-06 | 2002-09-13 | Ina Schaeffler Kg | GROOVE CAM MECHANISM |
| FR2821911A1 (en) * | 2001-03-06 | 2002-09-13 | Ina Schaeffler Kg | GROOVE CAM MECHANISM |
| WO2009090749A1 (en) * | 2008-01-18 | 2009-07-23 | Toyo Glass Machinery Co., Ltd. | Baffle, funnel, or blow head driving device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9421815D0 (en) | 1994-12-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |