AU2007203553B2

AU2007203553B2 - Resilient Mount With Load Cell

Info

Publication number: AU2007203553B2
Application number: AU2007203553A
Authority: AU
Inventors: Robert John Paron
Original assignee: ROBERT PARON
Current assignee: ROBERT PARON
Priority date: 2007-07-30
Filing date: 2007-07-30
Publication date: 2010-10-28
Anticipated expiration: 2027-07-30
Also published as: AU2007203553A1

Description

1 Resilient Mount with Load Cell Field of the Invention. 5 This invention is directed to a resilient mount of special design and which can provide information regarding the condition of the mount and whether the mount is supporting the correct weight of the engine. The invention is also directed to a method to enable the engine to be properly balanced on the resilient mounts (to reduce vibration). The invention will be described with reference to a marine engine but it should be 10 appreciated that the invention may also be applicable to other types of engines. Background Art. Marine engines are mounted in position using one or more resilient mounts. Typically, 15 the engine will be mounted using four resilient mounts, although for larger engines, additional mounts may be used. Figure 1 illustrates a conventional marine engine mounted to a rail using conventional resilient engine mounts. Figure 2 illustrates a conventional type of resilient engine mount. 20 One form of the present invention is directed to a modification or an addition to this type of resilient mount to provide greater versatility. The term "resilient mount" will refer to the item, an example of which is illustrated in figure 2, and the term "engine mount" will refer to the part of the engine that is 25 attached to the resilient mount and which may comprise laterally extending steel lugs ( see reference numerals 11,12 in figure 1). Referring to the conventional type of resilient mount illustrated in figure 2, the mount has a steel base which can be bolted into position. An oil resistant elastomer element 30 (also called a "rubber element") is positioned on top of the steel base. A vertical steel threaded rod extends upwardly and a number of lock nuts are threaded onto the rod. The lowermost lock nut is positioned above the rubber element and a steel washer is positioned between the lock nut and the rubber element. In use, the marine engine 2 contains laterally extending engine mounts in the form of steel lugs (see 11, 12 in figure 1) which are welded or bolted to the engine and which contain an opening through which the threaded rod can pass. The lock nuts are locked above and below the steel engine lugs and the engine is now mounted in place. 5 It is very important that the engine is balanced on the resilient mounts and that a situation does not occur where one resilient mount supports a much greater or lesser load than the other resilient mounts. This can cause the engine to vibrate. This is especially important in respect of marine engines which are connected to a propeller 10 shaft as any excessive vibration can damage the propeller shaft bearings. Excessive vibration can also damage gearbox bearings and generator bearings particularly when the engine is in a static situation. One form of the present invention is directed to an apparatus and a method which can 15 enable an engine to be balanced with greater accuracy and which can also enable the resilient mounts to be checked from time to time. It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the 20 common general knowledge in the art in Australia or in any other country. Object of the Invention. It is an object of the invention to provide an improved mounting for engines (and 25 especially marine engines) and which may overcome at least some of the above mentioned disadvantages or provide a useful or commercial choice in the marketplace. In one form the invention resides in a method for mounting an engine to resilient mounts, the method comprising attaching the engine to the resilient mounts via engine 30 mounts whereby the engine mounts are positioned above one of the lock nuts on the resilient mounts, slightly lifting the engine such that the engine mounts do not bear upon the respective lock nuts, measuring the weight of the engine at or adjacent each engine mount, balancing the engine load on each engine mount, and then screwing up the lock 3 nut underneath each engine mount to support the engine. In another form, there is provided method for mounting an engine to resilient mounts of the type having lock nuts threaded on a threaded rod, the method comprising attaching 5 the engine to the resilient mounts via engine mounts whereby the engine mounts are positioned above one of the lock nuts on the resilient mounts, slightly lifting the engine mounts such that the weight of the engine mounts do not bear upon the respective lock nuts, measuring the weight of the engine at or adjacent each engine mount, balancing the engine load on each engine mount, and then screwing up the lock nut underneath 10 each engine mount to support the engine. In this manner, the engine can be properly balanced on the resilient mounts (typically about four mounts will be provided for an average size marine engine) and this will reduce vibration. 15 The weight on each resilient mount does not need to be identical to the weight on each other resilient mount. However, it is desirable that opposed pairs of resilient mounts have the same weight applied to them. As an example, the rear end of a marine engine may be heavier than the front end of the marine engine and the rear pair of resilient 20 mounts will support a greater weight than the front pair of resilient mounts but it is preferred that each of the rear pair of resilient mounts support an identical weight to stop the engine from vibrating. The resilient mount may be similar to a conventional mount an example of which is 25 illustrated in figure 2. However the mount may be manufactured of different materials including aluminium, alloys, plastics, composite materials and the like. Various types of engine mounts may be provided and it is envisaged that the engine mount will be of conventional design and attached to the engine by the engine 30 manufacturer. However, these engine mounts typically have an opening through which the threaded rod of the resilient mount can pass - this being quite conventional. Typically, an engine will have at least four extending engine mounts.

4 In the present invention, the weight on each engine mount is measured when the engine mount is on or adjacent the resilient mount and the weight can then be adjusted to balance the engine. Typically, the engine mount is attached to the resilient mount by which is meant that the threaded rod passes through the opening in the engine mount 5 prior to the load on the mount being calculated. In a particular example, the engine mount is attached to the resilient mount such that the engine mount rests on one of the lock nuts, and the engine mount is subsequently slightly lifted off the lock nut to determine the weight on that particular engine mount. 10 A lifting means can be provided to lift the engine mount. The lifting means may comprise a frame or member having at least one portion that can engage with, or relative to the engine mount such that lifting of the frame cause the lifting of the engine mount. In an example, the lifting frame/member may comprise a portion that extends underneath part of the engine mount such that lifting of the lifting frame causes the 15 engine mount to be lifted. It is preferred that the frame is lifted by winding up a nut which is on the threaded rod on the resilient mount. This nut can be called a "lifting nut" for the sake of convenience. The frame may have a portion that can be pushed up by this lifting nut, 20 and thereby causing the frame to be lifted and thereby causing the engine mount to be lifted. The lifting distance need not be large and may be between 1-10 mm. 25 A load measuring means is typically provided to measure the load on the engine mount when the engine mount has been lifted off the lock nut on the threaded rod and which is below the engine mount. A preferred type of load measuring means will be a load cell. The load cell is a device 30 which is known and which provides an electric signal when a load is applied to the load cell and the signal can be measured to determine the load. It is preferred that the load cell is positioned above the lifting nut and below the frame 5 to measure the weight on the engine mount. As an example, as the lifting nut is wound up, it will push the load cell against the frame and continued winding up of the lifting nut will ultimately cause the engine mount to be slightly lifted and the load cell can then determine the load. 5 It is preferred that each resilient mount is provided with a load measuring means and a lifting means, to enable the weight on that particular engine mount to be measured. In one form of the invention, it is envisaged that the load cell and the lifting means will 10 be kept permanently in place when the engine has been mounted and balanced which enables the engine to be re-balanced from time to time and enables any deterioration in a resilient member to be noted. In another form of the invention, it is envisaged that the load cell and the lifting means 15 will be removed after use. Another advantage of the particular lifting method is that as the engine mount is lifted off the lower lock nut, the lifting means is such that the load will be transferred on to the threaded rod of the resilient mount. Thus, this particular lifting method is different 20 from using a separate crane or something else to lift the engine off the resilient mount. This particular lifting method causes a load to be applied to the rubber element of the resilient mount and the deflection (compression) of the rubber element will show if the rubber element has deteriorated and therefore requires replacement. 25 As an example, the resilient mount can be "preloaded" and the load cell can accurately measure the pre-loading amount. The manufacturer's specification of the resilient mount will then advise how much the rubber element should compress if the rubber element is in a sound condition. If the compression is greater, the rubber element has deteriorated and the resilient mount should be replaced. 30 Therefore, one advantage of the present invention is that it enables (a) the engine to be balanced and (b) the resilient mount to be tested all in one general operation.

6 In a particular example, a marine engine can be mounted to four separate resilient mounts. The engine mounts that are attached to the rear resilient mounts can then be slightly lifted by winding up the lifting nut on each rear resilient mount, and the load cell on each resilient mount can be used to measure the load on each rear engine mount. 5 The load should be about the same but if it is not, one lift nut can be lifted slightly further and/or the other lift nut can be rotated the other way and this will cause the weight of the engine to be redistributed until the weight is about equal. When the weight (as read by each load cell) is about the same, the lower lock nut can be wound up until it supports the weight of the engine mount. An upper nut can then be wound down 10 to lock the engine mount on the resilient mount between the upper and lower lock nut. The engine is now balanced. In another form the invention resides in a resilient mount for an engine, the resilient mount further comprising a load cell and a lifting means, the lifting means enabling the 15 engine mount to be slightly lifted. In another form the invention resides in a mounted engine (and particularly a marine engine) comprising an engine, engine mounts extending from the engine, resilient mounts to which the engine mounts are attached, and a load cell operatively associated 20 with each engine mount to measure the load on each engine mount. In this form of the invention, a lifting means may also be provided to enable the engine mount to be slightly lifted when required. The lifting means may be substantially as described above or below. 25 Brief Description of the Drawings. An embodiment of the invention will be described with reference to the following 30 drawings in which:. Figure 1. Illustrates a known type of engine attached to four resilient mounts (only two mounts being visible). Figure 2. Illustrates a known type of resilient mount.

7 Figure 3. Illustrates an engine mount (generally L-shaped steel lug) attached to the threaded rod of the resilient mount and resting on the lower lock nut. Figure 3 also illustrates a load cell supported on top of the lifting nut. Figure 4. Illustrates the lifting means in position with an upper part of the lifting 5 means being on top of the load cell and a lower part of the lifting means being positioned underneath the engine mount. Figure 5. Generally illustrates the position of figure 4 from a different angle but more clearly illustrating how the L-shaped steel lug (engine mount) is supported by the lower lock nut. 10 Figure 6. Illustrates how winding up of the top lifting nut underneath the load cell causes the lifting means to lift the engine mount (L-shaped steel lug) the lower lock nut thereby transferring the entire weight of the engine mount onto the threaded rod of the resilient mount and via the load cell to enable the weight on the engine mount to be accurately calculated by the load cell. 15 Best Mode. Referring initially to figure 1, there is illustrated an engine 10 containing engine mounts 11, 12, each mount being formed with a central opening. A resilient mount 13 (see also 20 figure 2) comprises a steel base 14, a rubber element 15, a steel threaded rod 16, a lower lock nut 17, a washer 18 which is below the lower lock nut 17, and upper lock nuts 9. This type of resilient mount is known in the marketplace. The threaded rod 16 passes through the opening in the engine mount 11, 12 (see figure 1), and the engine mount is supported by the lower lock nut 17 and is clamped in place by the upper lock nuts 19 25 this being quite conventional. In practice, there will be four resilient mounts and only two are illustrated in figure 1. Of course, on larger engines, there may be more than four resilient mounts. Referring now to figures 3 - 6, these illustrations describe an embodiment of the 30 invention. Referring initially to figure 3, there is illustrated a steel L-shaped engine mount 11 with the lower portion containing an opening to enable it to extend over the threaded rod 16 of the resilient mount. The engine mount 11 is supported by the lower lock nut 17 this nut being particularly illustrated in figure 5.

8 An upper part of threaded rod 16 contains an upper lock nut which can be seen as a lifting nut 20, but which may also function as one of the upper lock nuts 19. On top of lifting nut 20 is a load cell 21. 5 Referring now to figures 4-6, a lifting means is provided. In the embodiment, the lifting means comprises a somewhat C or U shaped strong steel member 22 which has a substantially solid top wall 23 which sits on top of load cell 21 (see for instance figure 6), and which contains a pair of extending lower steel finger members 24 (see 10 particularly figure 5) which hook underneath the lower part of engine mount 11. The lifting nut 20 (see particularly figure 6) can be wound up and in doing so, will lift the load cell, and because the load cell is underneath the top wall 23 of the lifting means 20, the lifting means will also lift by a few millimetres. Consequently, the lower steel 15 fingers 24 of the lifting means will lift the engine mount 11 off the lower nut 17 by a few millimetres this being illustrated in figure 6. In this position, the entire weight of the engine mount is supported by the lifting means and because the load cell is underneath the lifting means, the load cell will accurately measure the weight of the engine mount. 20 In use, the lifting nut on each resilient mount will be lifted such that the entire engine is being supported by each lifting means and therefore the load cell on each resilient mount can accurately measure the weight on each engine mount. 25 The engine can then be balanced by rotating the lifting nut 20 on each resilient mount either clockwise or anticlockwise until the desired balance is achieved. Typically, all the rear resilient mounts should bear the same weight and all the front resilient mounts should bear the same weight, but the weight on the rear mounts may be different than the weight on the front mounts. 30 Once the desired balance is achieved, the lower lock nut 17 can be wound up tightly underneath each engine mounts to transfer the load on to the lower lock nut.

9 If the load cell and the lifting means is of a removable type, these can be removed from the resilient mount. However, it is also possible for the resilient mount to be redesigned to contain a load cell and, if necessary, a lifting means which is always part of the resilient mount. 5 It is envisaged that the load cell will contain some form of socket or plug such that an electric wire can be attached when a measurement is to be made but when not required, the electric wire can be removed. It is also envisaged that a digital readout can be attached to the load cell when required. A wireless system is also envisaged. 10 Another advantage of the present invention is that the condition of the resilient mount can also be determined. To explain, an accurately measured weight (pr-eload) can be placed on the rubber element of the resilient mount by placing an accurately measured load on the threaded rod 16. The load cell enables this accurate measurement to be 15 made. Typically, the lifting nut can be adjusted such that a predetermined load is applied to the rubber element and the load can be from the engine mount. The manufacturer of the resilient mount will have provided tables which will give an acceptable deflection (compression) of the rubber element for a particular pre-load. As an example, the manufacturer's tables may specify that the rubber element will be in a 20 sound condition if it compresses by say 3 mm when a 200 kg load is applied. The required load can be applied using the lifting nut and can be measured using the load cell and the deflection of the rubber element can then be measured. If the amount of deflection of the rubber element is excessive, the element has deteriorated and the resilient mount can be replaced. 25 Throughout the specification and the claims (if present), unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers. 30 Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

10 Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention . Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from 5 the spirit and scope of the invention.

Claims

1. A method for mounting an engine to resilient mounts of the type having 5 lock nuts threaded on a threaded rod, the method comprising attaching the engine to the resilient mounts via engine mounts whereby the engine mounts are positioned above one of the lock nuts on the resilient mounts, slightly lifting the engine mounts such that the weight of the engine mounts do not bear upon the respective lock nuts, measuring the weight of the engine at or adjacent each engine mount, balancing the engine load on 10 each engine mount, and then screwing up the lock nut underneath each engine mount to support the engine.

2. The method of claim 1, wherein the engine mounts have an opening through which the threaded rod of the resilient mounts extend, the resilient mount 15 having a nut below the engine mount and a nut above the engine mount.

3. The method as claimed in any one of the preceding claims, wherein the weight of the engine is measured using a load cell operatively associated with the resilient mount. 20

4. The method of claim 3, wherein the load cell, in use, is on top of the threaded rod.

5. The method as claimed in any one of the preceding claims, comprising a 25 lifting member to lift the engine mount, each resilient mount having a lifting member.

6. The method as claimed in claim 4 and claim 5, wherein the lifting member has a portion which is positioned above the load cell and has a portion which is positioned below the engine mount such that lifting of the lifting member causes the 30 engine mount to be lifted.

7. The method as claimed in claim 6, wherein each resilient mount is provided with a lifting nut which is engaged to the threaded rod whereby rotation of the 12 lifting nut in one direction causes the lifting nut to travel up the threaded rod and contact the load cell and lift the load cell, the load cell being below the lifting member such that the lifting member is also lifted which, in turn, causes the engine mount to be lifted. 5

8. The method as claimed in claim 7, wherein each resilient mount is provided with a load cell and the lifting member, and the lifting nut can be rotated in either direction to adjust the weight on the engine mount thereby enabling the engine to be balanced, and thereafter, a lower nut on each resilient mounts can be wound up 10 underneath the engine mount to take the load of the engine mount.

9. The method as claimed in any one of the preceding claims, wherein the condition of the resilient mount can also be determined by placing a preset load on the resilient mount, the preset load being provided by a weight on the engine mount, and 15 then measuring the deflection of the rubber element on the resilient mount to determine the condition of the rubber element.

10. An engine mounted to at least one resilient mount using the method as claimed in any one of the preceding claims. 20

11. A resilient mount able to mount an engine according to any one of the preceding method claims, the resilient mount having a rubber element, an upstanding threaded rod, an upper lock nut and a lower lock nut, an engine mount being adapted to be positioned between the upper lock nuts and the lower lock nut, and a load cell 25 supported by the threaded rod.

12. The resilient mount as claimed in claim 11, further comprising a lifting member. 30

13. An engine mounted to at least one resilient mount of the type claimed in claim 11 or claim 12.

14. A method substantially as hereinbefore described and with reference to 13 the accompanying illustrations.

15. A resilient mount substantially as hereinbefore described and with reference to figures three-six.