GB2168462A

GB2168462A - A lubricating appliance

Info

Publication number: GB2168462A
Application number: GB08529427A
Authority: GB
Inventors: Hermann Stolz
Original assignee: Mato Maschinen und Metallwarenfabrik Curt Matthaei GmbH and Co KG
Current assignee: Mato Maschinen und Metallwarenfabrik Curt Matthaei GmbH and Co KG
Priority date: 1984-12-15
Filing date: 1985-11-29
Publication date: 1986-06-18
Also published as: GB8529427D0; DE3445881C2; GB2168462B; DE3445881A1

Abstract

A hand-held device for dispensing lubricant e.g. grease, under pressure, comprises, between its lubricant inlet and outlet connectors (3,4), a valve adapted to be actuated by a trigger (20). The valve comprises a valve rod (7), a valve seat (8), a moving valve member (9) and a closing spring (10). The valve rod (7) in the valve seat (8) extends through a hole (13) remote from the valve member and is able to be shifted axially by a trigger (20). In the bore (13) of the valve seat (8) there is a choke member (22). <IMAGE>

Description

SPECIFICATION A lubricating appliance The invention relates to lubricating appliances for grease and other lubricating material, and more especially but not exclusively to such a device connectible with a lubricant container or a source of lubricant under pressure and having a hand lever controlled valve for controlling lubricant flow from an inlet connector to an outlet connector in a housing. The valve has a valve rod, a valve seat, a moving valve member and a valve spring. The valve rod in the valve seat extends through a hole remote from the valve member and is able to be moved axially by the hand lever.

Grease guns constructed on these lines are in wide general use and in many cases are able to completely satisfy requirements. This is more especially the case since certain improvement have been made (see the German patent specifications 1,022,434 and 1,038,349) making it possible to meter out grease or other lubricant supplied under a high pressure.

Due to the incompressibility of the lubricant there are disadvantages with such grease guns inasfar as when the valve is opened undesired pressure surges occur so that in the first instant the lubricant issues from the lubricating appliance under a high pressure and this is followed by an equally sudden drop in the pressure which then becomes stabilized at the pressure level of the pressure source. For many applications such high pressure surges are undesirable, more especially because the immediate emergence of grease or other lubricant is uncontrolled and it fails to be proportional to the stroke of the lever of the trigger of the lubricant dispensing appliance.

Therefore one object of the present invention is to devise measures for avoiding initial pressure surges and the uncontrolled emergence of lubricant caused thereby.

In order to achieve this or other objects appearing in the course of the present specification, the invention consists in a lubricant dispensing appliance connectible with a source of lubricant under pressure, comprising a housing, an inlet connector, an outlet connector, means defining a duct connecting said inlet with said outlet connector, a valve in said duct, a hand lever for operation of said valve, said valve being made up of a valve rod, a valve seat with a hole leading therethrough, a movable valve member and a valve spring, said valve rod in the valve seat extending through a hole remote from the valve member and being able to be moved axially by the lever, said appliance further comprising a choke member placed in the hole of the valve seat.

The moving valve member controlled by the trigger or hand lever makes it possible for flow to take place freely, as has so far been the case in the prior art, when the valve is opened. The lubricant, such as a grease, however has to flow past the valve seat face on a choke member, which provides an intentional restriction in the free cross section as present in prior art devices. As a result it is not possible for any pressure peaks to occur right after opening the valve to the extent so far experienced. The pressure of the lubricant in fact only increases in step with the motion of the trigger, more especially when the choke body opens up the flow cross section gradually as is preferably intended.

Further features of the invention will be gathered from the specification and the claims in conjunction with the drawings.

The invention will now be described with reference to the accompanying drawings showing two embodiments thereof.

Figure 1 is section taken through a handheld lubricating appliance.

Figure 2 shows a detail in section and on a larger scale with the valve in the shut position.

Figure 3 is a section similar to that of Fig. 2 on opening the valve.

Figure 4 shows a section similar to that of Figs. 2 and 3 with the valve in the opened condition.

Figure 5 is a section of further form of the invention on a larger scale.

Figure 6 is a graph to show changes in pressure against the degree of motion of the trigger in the opening direction.

A hand lubricant dispensing appliance 1 as shown in Fig. 1 comprises a tubular housing 2 designed to simultaneously serve as a handle, with an inlet connector 3 and a tubular outlet connector 4 with a thread 5 for connection with a nozzle or the like. The moving part of a valve is placed in a through hole 6 in the housing 2. The hole has a number of different sections with different diameters. The valve is made up of an axially moving valve rod 7, a valve seat 8, a valve member 9 for shutting off the flow of lubricant and a valve spring 10. The valve spring 10 engages a hollow bush 11 and carries a plug 12 with the moving valve member 9, same being preferably in the form of a ball.

The valve seat 8 has a cylindrical hole 13 and a conical or part-spherical valve seat face 14.

In the shut position of the valve the valve rod 7 has its end, serving as a choke member 15, in the hole 13 of the valve seat 8 and on axial displacement the valve member 9 moves clear of the valve seat face 14 against the force of the valve spring 10. The other end 16 of the valve rod 7 extends through a guide bushing 17 and has its convex end face in a socket 18 on an arm 19 of the trigger 20 or hand lever. The guide bushing 17 furthermore terminates the through hole 6 in the housing 2.

The choke member 15 is conical in the embodiment of the invention shown in Figs. 1 through 4. In the shut setting as viewed in Fig. 2, it is in the cylindrical hole 13 of the valve seat 8. On opening the valve by axial displacement of the valve rod the choke member 15 does not immediately emerge from the cylindrical hole 13, since its outer limiting edge 21 co-defining the flow cross section and having a large diameter is spaced from the valve seat face 14 in the shut position.

As long as the choke member 15 is still within the hole 13 when the valve is being opened, its function is fully effective and it is only on reaching the position shown in Fig. 3 that the cross-section limiting edge 21 of the choke member 15 is adjacent to the valve seat face 14 with the consequence that the free cross section is gradually cleared and opened in a way dependent on the form of the choke member 15. It is only when the choke member 15 has completely, or more or less completely, cleared the hole 13 in the valve seat 8 as in Fig. 4 that the full cross section is available for the emergence of the grease or other lubricant.

Owing to the choke action of the choke member 15 the rate of flow will be seen from the graph of Fig. 6 to be initially very low on opening the valve and then to gradualy increase in accordance with the form of the choke member 15 until the maximum value is attained. The undesired pressure surges so far produced in known appliances accompanied by the emergence of a large amount of grease do not occur. The excessive rate of flow in such known systems has been marked by the broken line in Fig. 5.

In order to ensure that the flow-controlling outer edge 21 of the valve only comes into a position adjacent the valve seat face 14 after a comparatively long stroke of the valve rod, the choke member 22 of the valve 23 of the working example shown in Fig. 5 is fusiform or barrel-shaped with a convex outer face. In place of a sharply defined edge co-defining the flow cross section this choke member 22 has an annular face 24.

Furthermore the transition from the major diameter to the minor diameter equal to that of its adjoining valve rod 25 is initially less than in the case of a conical choke member 15, as in Figs. 1 through 4, if there is a barrel shaped or fusiform choke member 22. The rate of flow through the valve is therefore more accurately controlled by varying the degree of opening of the valve.

Inasfar as Fig. 5 shows parts which are the same as the corresponding parts in Figs. 1 through 4, they bear the same reference numerals.

The function of the choke member 15 and of the choke member 22 may furthermore be improved in addition if the valve rod 7 or 23, respectively, is able to be very exactly positioned with the help of the trigger 20. In order for this to be possible, the bearing of the trigger or hand lever 20 is provided with a shifting bearing face 26 as shown in Figs. 2 through 4. In the shut position of Fig. 2 this bearing face 26 is essentially in the end-on projection plane of the valve rod 7 and on opening the valve moves out of this plane.

The center point of the bearing face 26 is in the shut position as shown in Fig. 2 at a distance a from the axis of the valve rod 7.

On opening the valve the bearing face 26 moves away from the axis 27 and in the position shown in Fig. 3 will be at the distance b from such axis. When the valve is completely opened as in Fig. 4, the bearing face 26 will have moved into a position in which it is at the distance c from the axis 27. The change in the distance a through c of the bearing face 26 from the axis 27 is achieved by a slight curvature of its surface, which runs towards the free end 28 of the arm 19 and then merges with a sharp arcuate curve. The effective length of the arm 19 of the trigger 20 in relation to the axis 27 undergoes the change in accordance with the distance a and the distance c so that the leverage changes as well.

On actuating the trigger 20 there is therefore initially only a small axial displacement of the valve rod 7 and it is only after a greater motion of the trigger 20 that the valve rod 7 is moved into its opening position as shown in Fig. 4.

The bearing means for the trigger 20 and its arm 19 is only by way of the free end 16 of the valve rod 7 and a support part 29 on the side, remote from the valve rod 7, of the arm 19. With the help of the valve spring 10 on the arm 19 is urged onto the support part 29 and then held in this position by the fusiform end 16, extending into the socket 18, of the valve rod 7.

In order to secure the support part 29 in place, use is made of a half shell 30 cooperating with a second half shell, not shown in Fig. 1, to fit around a part of the housing 2 and the tubular outlet connector 4. The support part 29 is adjustably secured to the half shell 30 by means of a pivot 31 and a bracket 32 with a slot 33 and an attachment screw 34. With the help of this arrangement it is possible for the support part 29 to fixed in place accurately so as to keep to tight tolerances.

The surface of the supporting part 29 facing the arm 19 is preferably flat.

Claims

1. A lubricant dispensing appliance connectible with a source of lubricant under pressure, comprising a housing, an inlet connector, an outlet connector, means defining a duct connecting said inlet with said outlet connector, a valve in said duct, a hand lever for operation of said valve, said valve being made up of a valve rod, a valve seat with a hole leading therethrough, a movable valve member and a valve spring, said valve rod in the valve seat extending through a hole remote from the valve member and being able to be moved axially by the lever, said appliance further comprising a choke member placed in the hole of the valve seat.

2. A lubricant appliance as claimed in claim 1 wherein the choke member is cylindrical around the shut position of the valve and the choke member is conical.

3. A lubricant appliance as claimed in claim 1 wherein said choke member is barrelshaped.

4. A lubricant appliance as claimed in claim 1 wherein said valve member is a part of said valve rod.

5. A lubricant appliance as claimed in claim 1 wherein the choke member has an end with a greater diameter than an opposite end thereof, said larger end having an outer edge for controlling flow of lubricant through said valve, said outer edge being spaced from the valve seat in a shut position of said valve.

6. A lubricant valve as claimed in claim 1 comprising a pivot bearing for said hand lever, said bearing being adapted to change its axis of pivot in accordance with a rocking motion of said lever.

7. A lubricant appliance as claimed in 1 wherein said lever is adapted to engage an end of the valve rod and has a bearing face resting on said housing in a plane coinciding with the projection of the rod end thereon and on opening of the valve moves out of such position.

8. A lubricant appliance as claimed in claim 1 wherein said lever comprises an arm with a free end and with an arcuate bearing face, there being a flat support part therefor on said housing.

9. A lubricant appliance as claimed in claim 8 wherein said support part is adjustable.

10. An appliance as claimed in claim 1 substantially as described above with reference to and as illustrated in Figs. 1 through 4 of the accompanying drawings.

11. An appliance as claimed in claim 1 substantially as described above with reference to and as illustrated in the figure 5 of the accompanying drawing.