AU634718B2 - Grease gun - Google Patents

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION 6 3 4 7 1 (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: *R'lated Art: *o *ee A co11 $'9 2 (V a Name of Applicant: .~dress

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of Applicant: Actual Inventor(s): fo :4.ress for Service: GRAHAM ERIC ALAN BISHOP and GEORGE MORTON DRINKWATER 311 Rowan Street, Golden Square Victoria, 3555 Australia; and 3 Abel Street, Bendigo, Victoria 3550 Australia; respectively GRAHAM ERIC ALAN BISHOP and GEORGE MORTON DRINKWATER DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Complete specification for the invention entitled: "GREASE GUN" The following statement is a full description of this invention, including the best method of performing it known to us 1 -2- A GREASE GUN AND FILLER APPARATUS FOR SUCH A GUN The present invention relates to a grease gun and also to filler apparatus for charging grease into a reservoir of the gun.

It is known to provide a grease gun with a dispensing mechanism which is pneumatically-operated to cause discharge of grease under high pressure from the gun. Such guns conventionally comprise a reservoir which is substantially re-filled manually by paddling grease into the reservoir. This is relatively time-consuming and rarely results ii complete filling of the reservoir and can also be a messy operation.

According to the present invention, there is provided a pneumaticallyoperated grease gun comprising a body, a reservoir attached to the body for containing grease to be dispensed, a firstyai-actuated piston movable in one direction through the reservoir for discharging grease from the reservoir into a chamber for subsequent ejection from the gun by a second~, i-actuated piston, an inlet leading into the reservoir from externally of the reservoir to permit 20 replenishment of the reservoir by forcing grease through the inlet so that the first wc. -JRfiW-actuated piston is displaced in a reverse direction, and valve means for closing the inlet after replenishment of the reseroir.

The invention also provides a grease gun as defined above in combination *i 25 with filler apparatus for pumping grease from a container into the reservoir of the gun, said filler apparatus comprising means for mounting the apparatus releasably on the container, a pump actuable to pump grease from the container, said pump having an inlet which, when the apparatus is mounted on the container, lies adjacent the bottom of the container, sealing means for placement above the grease within the container to substantially prevent ingress of air as the level within the container is lowered, and drive means acting on the sealing means for forcing the sealing means towards the bottom of the container as the level of 921126,rshspe.010,gundispense.spe,2 -3grease within the container lowers, the pump having an outlet arranged for communication with the inlet of the reservoir.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a section through a grease gun in accordance with a preferred embodiment of the invention; Figure 2 is a section through an inlet valve of a reservoir of the gun; Figure 3 is a longitudinal section through one form of filler apparatus for use with the gun; Figure 4 is a section through an outlet coupling of the filler apparatus; and Figure 5 is a longitudinal section through another embodiment of the filler apparatus.

With initial reference to Figure 1 the gun comprises a body 2 having a handle 4 with an inlet 6 for air from a high pressure air line. The handle 4 also includes a trigger 8 in the form of a control knob of a valve 10 which is opened by depressing the trigger to open and close an air passage 14 leading from the air inlet 6. A lubricant reservoir comprising a casing 16 of cylindrical form is releasably attached to the body 2 by means of a clamping rod 18 which extends axially through the reservoir 16, the clamping rod 18 being threaded at its inner end into a threaded seat 20 mounted in the gun body 2 and having a knob 22 at its outer end. The knob 22 can be rotated to screw the clamping rod 18 into and ei'• *out of the threaded seat 20 whereby to permit engagement and release of the reservoir casing 16 from the gun body 2. The clamping rod i8 includes an internal passage 18a which opens at its inner end into a chamber 24 which communicates with the air passage 14 downstream of the valve 10. An outer end of the internal passage 18a discharges at 18b into the interior of the reservoir .:oe.i S"casing 16 adjacent an outer end wall 26 of the casing 16. The clamping rod 18 S' 30 also mounts a piston 28 displaceable along the length of the resrvoir casing 16.

Lubricant to be dispensed is contained within the reservoir casing in a chamber /cri.. 30 defined between the piston 28 and the body 2 of the gun, End actuation of the 921 127,rshspe.01,gundispense.spe,3 -4trigger 8 causes air to pass from air passage 14 through the clamping rod 18 to be discharged via outlet 18b into a pressure chamber 32 defined between the piston 28 and the outer end wall 26 of the casing 16 to thereby advance the piston 28 towards the inner end of the casing 16, the lubricant being discharged from the reservoir into an outlet passage 34 leading to a pressure discharge passage 36 in the gun body 2. The pressure discharge passage 36 leads to an outlet nozzle 38 incorporating a discharge valve which opens when a predetermined pressure of lubricant is obtained in the discharge passage 36 by an air actuated piston mechanism 37. The piston mechanism 37 is actuated by air fed through a passage 14a branching from the passage 14. The foregoing construction is substantially conventional for grease guns of this general type.

In accordance with the invention, the reservoir 16 is replenished with lubricant by feeding the lubricant into the lubricant chamber 30 through an inlet 40, by means of the filler apparatus to be subsequently described. Charging of lubricant through the inlet 40 causes the piston 28 to be displaced towards the outer end wall 26 of the reservoir casing 16 and in the fully charged position, the piston 28 lies adjacent the end wall 26 and causes an indicator 42 to project from the end wall 26 to show the user that the reservoir is full. An indicator may also 20 be provided to show when the reservoir is substantially empty. The lubricant inlet carries a valve 44 (Figure 2) which co-operates with an outlet from the filler apparatus and which is closed to prevent reverse flow of lubricant through the inlet during discharge. Closure of the valve 44 can be effected manually or automatically; in the latter case, the valve 44 will be a one-way valve, for example a spring-loaded ball valve.

The configuration described above permits ease of charging of the reservoir without the need to remove the reservoir, although the reservoir is removable to permit replacement by a reservoir for a different grease.

With reference to Figures 3 and 4, filler apparatus for filling the reservoir of the gun shown in Figure 1 comprises a pump assembly 51 which is adapted to 921126,rsspe.01O,gundispense.sp,4 be releasably mounted on a drum 52 of lubricant. The pump assembly comprises a main mounting plate 53 adapted to be attached to the drum 52 of lubricant at the upper end thereof so as to form a lid for closing the drum, the pump assembly being releasably secured to the drum by latches 54 carried by the mounting plate 53 and which engage beneath an outwardly turned upper edge of the drum. The mounting plate 53 carries a lubricant pump having an outer housing 63 which extends downwardly through the drum to provide a lubricant inlet substantially at the bottom of the drum, the inlet being associated with a one-way valve 64.

The pump comprises a pumping cylinder 65 extending through the housing 63 and containing a pumping piston 66 of rod-like form actuated by a handle 67 at its upper end above the mounting plate 53. An outlet 68 extends from the upper end of the pump housing 63 above the mounting plate 53. in operation, an upstroke of the pumping piston 66 by drawing the handle 67 upwardly, serves to draw in lubricant from tne bottom of the drum through the inlet and one-way valve 64 at the foot of the pump housing. It will be seen that the diameter of the rod-like pumping piston 66 is less than the diameter of the cylinder 65, but due to the viscosity of the lubricant being pumped, there will be a seal formed by the lubricant between the piston and cylinder wall during the upstroke. A subsequent downstroke by pushing the handle 67 downwardly discharges the 20 lubricant upwardly through the annular space defined between the piston and the cylinder wall for discharge at the outlet 68, the one-way valve 64 at the inlet of the pump housing closing under the pressure exerted on the lubricant during the downstroke. A coupling 69 (Figure 4) is secured to the outlet 68 and is adapted to receive the end portion of inlet valve 44 of the grease gun reservoir 16 in order to charge the lubricant into the reservoir.

I:i .A latch 70 is provided to lock the pump handle 67 in a lower position to the mounting plate 53 so that the pump handle 67 can be used as a carrying handle for the filler apparatus. The gun itself may also be attachable to the filler .i 30 apparatus for storing the gun and also for carrying the gun.

The lubricant has a high viscosity and in order to provide an effective 921126,rshspe.010,gundispense-spe,5 -6pumping action, it is necessary to ensure that air is prevented from being drawn into the pump inlet during pumping. Air is excluded from entering the pump inlet by providing an air sealing plate 71 within the drum above the lubricant therein and which moves downwardly within the drum as the lubricant level falls.

It is to be noted that conventional lubricant drums are slightly tapered towards their bottoms to facilitate manufacture, and in view of the taper it is necessary to positively force the sealing plate 71 towards the bottom of the drum, particularly when the sealing plate 71 is within the lower part of the drum. The sealing plate 71 is of rigid construction having at its outer periphery flexible annular seals 72 which can deform sufficiently to accommodate the reduction in drum diameter as the plate 71 moves downwardly, while maintaining the peripheral seal. The plate 71 is driven downwardly by a drive system which, in the embodiment shown, is a mechanical drive system and which will now be described.

The mechanical drive system comprises a coarse thread 63a formed on the external surface of the pump housing 63 substantially along the entire length of the housing and which mounts a driven pinion 74 having an internal thread engaged with the thread 63a such that when the pinion 74 is rotated, it will be displaced axially along the pump housing 63. The driven pinion 74 is linked to 20 the sealing plate 71 by a connection 76 which permits the pinion 74 to rotate relative to the sealing plate 71 but which causes the sealing plate 71 to be o displaced axially with the driven pinion 74. Rotation of the driven pinion 71 is effected by means of a driving pinion 78 carried by a driving shaft 81 parallel with -•1the pump housing 63. The driving pinion 78 is mounted on the driving shaft 81 25 by a connection which permits the driving pinion 78 to rotate with the shaft 81 i but to move axially along the shaft 81 so as to follow the axial movement of the driven pinion 74. This can be accomplished simply by forming the shaft 81 of a non-circular section received within an aperture of similar section formed through the driving pinion 78. The driving pinion 78 is connected at its lower end to the 30 pressure plate 71 by a bearing 79 which permits rotation between the driving pinion 78 and the pressure plate 71 but which causes the driving pinion 78 to be ,drawn along the shaft 81 when the pressure plate 71 is axially displaced. The 921126,rshsje.1 O,gundispense.spef6 -7shaft 81 is rotated by a handle 82 at its upper end above the mounting plate 53.

As will be apparent, pumping of the lubricant into the reservoir of the gun by actuation of the handle 67 will cause the lubricant level within the drum to fall.

When the reservoir has been filled or during filling, the handle 82 is rotated to displace the driven pinion 74, and hence sealing plate 71, downwardly. It is to be noted that the driving mechanism is not intended to drive the sealing plate 71 so as to pressurise the lubricant within the drum, but rather to force the sealing plate 71 through the drum to follow the diminishing level of lubricant to prevent an air space being formed above the lubricant and which might result in air being drawn into the pump. The progressive displacement of the sealing plate 71 towards the bottom of the drum ensures that substantially all of the lubricant within the drum can be removed by the pump. When the drum has been emptied, the filler apparatus is removed from the drum and mounted on a fresh drum. In preparation for use with a fresh drum, the sealing plate 71 must be returned to the upper end of the pump housing 63 adjacent the underside of the mounting place 53, and this is achieved by rotation of the handle 82 in the reverse direction.

In the embodiment shown in Figure 5, the sealing plate 71 is mounted for 20 floating movement through a limited axial distance relative to the driven pinion 74. The driving pinion 78 is coupled to the sealing plate 71 in such a manner as to float along the driving shaft 81 with the sealing plate 71 and the axial length of the driving pinion 78 is such that the driving pinion 78 remains in driving engagement with the pinion 74 at the upper and lower limits of the possible floating movement between the sealing plate 71 and the driven pinion 74, the upper and lower limits of the floating movement being defined by stops 85 and 86 on the driven pinion 74. With this construction, the sealing plate 71 is able to Sfloat on the upper surface of the lubricant within the drum' as the level lowers during pumping. The extent of floating movement allowed is preferably such that several strokes of the pump sufficient to replenish the lubricant reservoir of the gun can be accommodated within the range of floating movement, the mechanical S drive system then being actuated at the end of the filling operation.

921 126,rshspe.010,gundispense.spe,7 -8- In this embodiment, preferably the connection between the driven pinion 74 and the thread 63a on the pump housing 63 is formed by diametrically-opposed half nuts 90 which can be moved between an inner position in which the half nuts are engaged with the thread 63a and radially outer, released, positions, movement of the half nuts 90 to the outer released positions being effected by levers 92 against the bias of springs which tend to urge the half nuts to the engaged positions. When the half nuts 90 are released from the thread 63a the assembly consisting of the sealing iplate 71, the driven pinion 74 and the driving pinion 78 can quickly be returned from a position at the lower end of the pump housing 63 when the drum 'as been emptied to the upper end of the pump housing 63 in preparation for use with a fresh drum. As will be apparent this will provide faster retraction of the sealing plate 71 and associated components than would rotation of the handle 82 in the reverse direction.

In a further modification instead of incorporating a driving pinion mounted on a separate shaft to displace a driven pinion and hence the sealing plate, the pump housing itself may be rotatable to co-operate with an element equivalent to the driven pinion, but held against rotation so that it is the rotation of the pump housing which causes the downwards displacement of the sealing plate.

The embodiments have been described by way of example only and modifications are possible within the scope of the invention.

ool oi 4 921126,rshspe.010,gundispense.sp,8

Claims (17)

1. A pneumatically-operated grease gun comprising a body, a reservoir attached to the body for containing grease to be dispensed, a first pneumatically-actuated piston movable in one direction through the reservoir for discharging grease from the reservoir into a chamber for subsequent ejection from the gun by a second pneumatically-actuated piston, an inlet leading into the reservoir from externally of the reservoir to permit replenishment of the reservoir by forcing grease through the inlet so that the first pneumatically-actuated piston is displaced in a reverse direction, and valve means for closing the inlet after replenishment of the reservoir.

2. A grease gun according to claim 1, further comprising indicator means operable to indicate when the reservoir has been fully replenished.

3. A grease gun according to claim 2, wherein the indicator means comprises means responsive to movement of the first pneumatically-actuated piston to an end position in said reverse direction.

4. A grease gun according to claim 3, wherein said indicator means 20 comprises a spring-loaded indicator member engageable by the first pneumatically- actuated piston as it approaches its end position.

5. A grease gun according to any one of claims 1 to 4, wherein the first air-actuated piston is mounted for movement along a hollow rod extending 25 centrally through the reservoir, the interior of the rod defining a passage leading into a pressure chamber defined in the reservoir behind the piston, such that air fed through the passage and into the pressure chamber forces the S: first pneumatically-actuated piston in said one direction.

6. A grease gun according to claim 5, wherein the rod is a clamping rod by which the reservoir is releasably clamped to the body of the gun. 921230,rshspe.01O,gundispense.spe,9

7. A grease gun according to any one of claims 1 to 6, wherein the valve means is a one-way valve which automatically opens in response to passage of grease through the valve to replenish the reservoir.

8. A grease gun substantially as hereinbefore described with reference to the accompanying drawings.

9. A grease gun in accordance with any one of the preceding claims in combination with filler apparatus for pumping grease from a container into the reservoir of the gun, said filler apparatus comprising means for mounting the apparatus releasably on the container, a pump actuable to pump grease from the container, said pump having an inlet which, when the apparatus is mounted on the container, lies adjacent the bottom of the container, sealing means for placement above the grease within the container to substantially prevent ingress of air as the level within the container is lowered, and drive means acting on the sealing means for forcing the sealing means towards the bottom of the container as the level of grease within the container lowers, the pump having an outlet arranged for communication with the inlet of the reservoir.

10. A combination according to claim 9, wherein the pump comprises a pump housing arranged to extend substantially along the longitudinal axis of the container, and the sealing means is mounted on the pump housing for move,.snt therealong by actuation of the drive means. 25

11. A combination according to claim 10, wherein the drive means comprises a driven member mounted for movement along the pump housing upon relative rotation between the driven member and pump housing, said driven member being coupled to the sealing means. 30

12. A combination according to claim 11, wherein the sealing means is mounted for limited axial floating movement relative to the driven member so as to move through a restricted distance downwardly relative to the driven member 921126,rshspe.010,gundispenspeiO -11 as the grease level lowers within the container.

13. A combination according to any one of claims 10 to 12, further comprising a driving member mounted on a driving shaft extending substantially parallel to the pump housing, the driving member being rotatable by the driving shaft to drive the driven member, the driving member being movable downwardly along the shaft as the sealing means moves downwardly.

14. A combination according to any one of claims 11 to 13, wherein the driven member is mounted on a thread formed on the pump housing and includes means engageable with the thread to permit movement of the driven member along the pump housing upon rotation of the driven member.

A combination according to claim 14, wherein the thread-engaging means is selectively releasable from the thread by operation of release means whereby to permit the driven member and sealing means to be returned rapidly to an upper end of the pump housing.

16. A combination according to any one of claims 9 to 15, wherein the pump is a manually-operated reciprocating pump, a handle of the pump also forms a handle for carrying the filler apparatus, and the apparatus further comprises means for locking the handle in a position to permit carrying. *o eoo o,* *o 921126,rshspe.010,gundispensespe,11 12-

17. A combination according to any one of claims 9 to 16, wherein the sealing means comprises a rigid plate having at an outer periphery a seal to engage a wall of the container. DATED this 26th day of September, 1992 GRAHAM ERIC ALAN BISHOP and GEORGE MORTON DRINKWATER By their Patent Attorneys DAVIES COLLISON CAVE i S i 921126,r-.hspe.10,gundspense.spe,12