RU2850485C2 - Device for installing cover - Google Patents

Abstract

FIELD: device for installing cover.

SUBSTANCE: invention relates to a cover installation device that can be used to install flexible covers (also known as dust caps) on joints, in particular, but not exclusively, constant velocity joints in vehicles, as well as joints between axles and drive shafts. A pneumatically controlled device for installing a cover on joints comprises a pneumatic actuator designed to be controlled, when in use, to stretch the cover, wherein the pneumatic actuator comprises a piston, wherein the piston is hollow and has an open end to allow a shaft to be inserted into it, over which a cover is to be fitted when the device is in use, and comprises a support surface, a plurality of rotatably mounted levers for receiving and stretching the cover, one end of each lever extending from the device to a free end, and the opposite end of each lever, beyond the point around which the lever is rotatable, is designed to contact the piston support surface, a user-operated self-resetting pressure relief valve, wherein the self-resetting pressure relief valve is located in the piston and is designed to allow or restrict the flow of fluid through the piston from one side of the piston to the other.

EFFECT: implementation of the possibility of installing flexible covers by means of the claimed device.

11 cl, 9 dwg

Description

Field of technology

The present invention relates to a boot installation device that can be used to install flexible boots (also known as boots) onto joints, in particular, but not exclusively, constant velocity joints in vehicles, as well as joints between axles and drive shafts.

State of the art

DE 10 2008 057 413 A1 discloses a device for installing a boot using a pneumatic cylinder piston assembly and a pneumatic cylinder to spread levers around which the boot is positioned for installation on a joint. The piston is moved using compressed air, and a pressure relief valve is integrated into the handle of the device near the user-operated valve to prevent excessive pressure buildup and, consequently, failure of the device (which could result in injury to the operator).

The problem with this device is that the pressure relief valve protrudes from the device, making it susceptible to damage. It is also accessible to the user, posing a risk of being tampered with or replaced, potentially rendering the device unsafe to operate.

Another problem with the said device is that the piston comes into contact with levers located near the hinges on which they are mounted, and thus the piston must apply a lot of force to spread the levers and tighten the boot.

Other existing boot installation devices feature a single-use pressure relief valve. If the pressure relief valve is activated, the device must be disassembled, the component replaced, or a qualified repair is required to restore normal operation.

The object of the embodiments of the present invention is to provide a device for installing a case that solves the problems present in existing devices.

Disclosure of the essence of the invention

According to one aspect of the present invention, a pneumatically controlled boot installation device is provided, comprising a pneumatic actuator configured to be controlled, in use, to stretch the boot, wherein the pneumatic actuator comprises a user-controlled valve and a self-resetting pressure relief valve.

Placing a self-resetting pressure relief valve within the pneumatic actuator reduces the risk of it being tampered with or otherwise damaged. The presence of a self-resetting pressure relief valve allows the user to continue using the device after activating the self-resetting pressure relief valve without the need for repair or replacement.

A pneumatic actuator may contain a piston, although other actuators, such as a bellows, can also be used. The piston may be located in a channel or channels that form a cylinder.

A self-resetting pressure relief valve can be located in the piston and can be configured to allow or delay fluid flow through the piston from one side of the piston to the other, thereby limiting the pressure differential between the opposite sides of the piston. If a self-resetting pressure relief valve is located in the piston, it is typically not easily accessible and therefore not susceptible to damage or tampering.

The self-resetting pressure relief valve can be located in a recess in the piston. This also prevents intentional or accidental contact with the self-resetting pressure relief valve. The self-resetting pressure relief valve can be located on the end face of the piston.

Other placement options are possible, and it is preferable that the self-resetting pressure relief valve be positioned so that it does not interfere with the tool's operation, for example, so that it is excluded from the tool's functionality. The self-resetting pressure relief valve can be located elsewhere than on the piston end face.

A self-resetting pressure relief valve may comprise an orifice and a valve element configured to close said orifice. A resilient element may be positioned to bias the valve element toward said orifice. The resilient element may be a flexible rod or a leaf spring. This arrangement allows for a self-resetting pressure relief valve with a significantly shallower depth than conventional self-resetting pressure relief valves that use a coil spring.

The opening may have a substantially circular cross-section. The valve element may comprise a plug. Said plug may have, at least in part, a substantially truncated cone shape.

The elastic element may be connected to the piston by means of a fastening element that presses it against two contact points located at some distance from each other on the piston to displace the element in such a way that it presses the valve element in the direction of the specified opening.

The elastic element and valve element can be manufactured from a single piece of material. For example, they can be molded, such as cast from a plastic material. Molding both components from a single piece of material simplifies manufacturing and reduces cost.

Alternatively, the elastic element and valve element may be formed from two separate blanks. These two separate blanks may be joined together using suitable fasteners. These two blanks may be made of different materials. For example, the elastic element may be made of a metal material, and the valve element may be made of a resilient material such as rubber.

The bore may comprise a passage in the piston. The bore may comprise a channel in the piston. The channel may have a substantially circular cross-section or may be substantially cylindrical.

The piston may be hollow and have an open end to allow the insertion of a shaft, over which a cover should be installed when using the device.

The piston may have a bearing surface that may be substantially in the shape of a truncated cone.

The device may comprise multiple pivotally mounted levers for receiving and extending the cover. One end of each lever may extend from the device to the free end, and the opposite end of each lever, beyond the pivot point, may engage the supporting surface. Positioning the lever end beyond the pivot point to ensure contact with the supporting surface is necessary to maximize the leverage available to the piston when actuating the levers.

Implementation of the invention

For a better understanding of the present invention, one or more embodiments thereof will now be described by way of example only and with reference to the accompanying drawings, of which:

Fig. 1 shows a perspective view of the device for installing the cover;

Fig. 2 shows a cross-section of the device along line II-II in Fig. 1;

Fig. 3 shows a view corresponding to the view shown in Fig. 2, of the device in the unfolded position;

Fig. 4 shows the end view of the device;

Fig. 5 shows a cross-section of the piston of the device;

Fig. 6 shows a partial exploded view of the internal piston of the device;

Fig. 7 shows a view corresponding to the view shown in Fig. 5 of a part of the piston of the device, depicting a self-returning pressure relief valve in the activated state;

Fig. 8 shows an exploded perspective view of the device; and

Fig. 9 shows a view corresponding to the view shown in Fig. 2 of the device during its operation.

As shown in the drawings, device 1 for installing a cover comprises a main body 2, which has a substantially cylindrical section. One end is open. The opposite end is closed and has a domed outer surface. An elongated handle 3 protrudes from the center of the dome. Main body 2 and handle 3 are molded integrally from a plastic material. A suitable material is glass-filled nylon.

The open end of the main body 2 is open into a substantially cylindrical internal channel which extends approximately two-thirds of the length of the substantially cylindrical and domed regions of the main body 2 (excluding the handle 3) and has a diameter equal to approximately 80% of the outer diameter of the substantially cylindrical section of the main body 2.

The inner channel leads to a second, smaller, coaxial, essentially cylindrical channel, the diameter of which is approximately one-third the diameter of the larger inner channel. This channel extends from the end of the larger channel through the domed end of the main body into the base of handle 3. The smaller channel has a length approximately equal to half the length of the larger channel. At the end of the smaller channel at the base of the handle, the diameter of the smaller channel decreases slightly in two stages, and then the channel is closed, except for a relatively small opening in the pipeline passing through handle 3.

Handle 3 is elongated and has a generally circular cross-section, the diameter of which gradually decreases in the direction from the main body to the free end. It is sized and shaped to allow the user to grasp it with one hand, and has a compartmentalized support structure. A conduit extending through handle 3 provides a connection capable of transferring fluid between the end of the smaller channel in main body 2 and hose fitting 4 at the free end of handle 3. User-controlled valve 5 is located in the conduit near main body 2. The valve is positioned such that the user can control the flow of fluid through the conduit from the hose fitting into the device, and so that the fluid can exit the device into the atmosphere.

A casing 6 made of rubber or similar material is placed around the handle 3 to ensure its comfortable grip by the user.

An annular end plate 7, made of the same material as the main body, is attached to the open end of the main body 2. The internal diameter of the end plate 7 is approximately equal to the diameter of the smaller channel in the main body 2. The end plate 7 is attached to the end surface of the main body 2 by eight screws 8, passing axially through corresponding passages uniformly distributed around the end plate 7, through corresponding passages in the flange formed around the open end of the main body 2, and into corresponding nuts 9.

A set of eight pivotably mounted metal levers 10 is located on the open end of the main body 2. The levers 10 are elongated and each of them is pivotally mounted on a corresponding shaft held in opposite recesses in the end plate 7 and the end surface of the main body 2. The levers 10 are located at equal intervals around the end plate 7. The levers 10 are configured to rotate about a point approximately one-sixth of the way along their length. The shorter S-shaped section of each lever 10 extends radially inward and into the opening in the main body 2. The remainder of the lever 10 extends with a much more elongated double bend in the direction from the body.

Each lever 10 is mounted so as to be able to rotate about an axis directed tangentially to the annular end plate 7. A spiral spring 11 is located in the main body 2 between the end plate 7 and the ends of the levers 10. The spring 11 is sized such that it rests on the end plate 7 and the S-shaped sections of the levers, and presses the levers 10 toward their closed position. The spring 11 tapers from the larger end, which is in contact with the levers 10, to the smaller end, which rests on the end plate 7.

The piston 12 is located in cylindrical channels in the main body 2. The piston 12 is molded from a plastic material, in particular, a suitable material is polyamide (nylon), and comprises a hollow, substantially cylindrical section formed by a cylindrical wall with a closed end surface. A certain outer diameter of this section ensures a tight sliding fit of the piston 12 in the smaller channel in the main body 2, and this section has a length approximately equal to the length of the smaller channel. At the opposite end of said section relative to the end surface, the cylindrical wall of the piston 12 extends at an angle of 90° in the radial direction outward and forms an annular section with an outer diameter that is approximately twice as large as the cylindrical section. Further, said wall extends at an angle of approximately 45° and is an inclined wall that extends in the radial direction outward to a location in which the outer edge of the wall ensures a tight sliding fit with the large channel in the main body 2.

The inner surface of the inclined wall is slightly convex in cross-section and provides a support surface substantially in the form of a truncated cone, which, during use, comes into contact with the ends of the brackets 10, as discussed below. When the levers 10 are moved to the closed position, they press the piston 12 towards the handle 3. When the levers 10 are in their fully closed position, the piston 12 moves to a fully retracted position, in which the end surface of the piston 12 facing the handle 3 rests against the first protrusion formed in the smaller channel inside the main body 2.

A pair of ribs 13, 14 project approximately from the midpoint of the outer side of the inclined surface of the piston 12. One rib 13 projects substantially in the axial direction in the direction from the inclined surface and ends substantially on the plane of the annular section of the piston 12. In the direction of the free end of the rib 13, a projection 15 is formed extending radially outward. The outer diameter of this projection 15 is so much smaller than the inner diameter of the larger channel in the main body 2 that it is located at a certain distance from the said channel. The radial outer edge of the projection 15 is curved in such a way that its diameter slightly decreases in the direction of the free end of the rib 13 such that it has a generally wedge-shaped profile. The second rib 14 projects radially from the inclined surface and extends in such a way that it has a diameter that is essentially equal to the largest diameter of the inclined surface, thereby ensuring its tight fit with sliding in the large channel of the main body 2. The movement of the second rib 14 together with the inclined surface and the inner wall of the cylindrical channel is limited by an annular region with a triangular cross-section.

An elastic circular sealing ring 16 made of rubber or a similar material is located in the space bounded by ribs 13, 14 and projection 15 on the piston, as well as the inner wall of the cylindrical bore. The sealing ring moves within the bore along with the piston and forms a seal between the piston and the bore.

The inner side of the end surface of the piston 12 has a recessed, generally rectangular segment 17. A substantially cylindrical channel 18, forming an opening for the valve, passes through the end surface of the recessed segment. A recessed, straight, parallel lateral groove 19 is formed on the non-recessed section of the end surface. Said groove extends substantially at a right angle to the straight edge of the recessed segment 17 and connects with the recessed region 17. Groove 19 is positioned such that a line passing along the center of groove 19 and parallel to its sides passes through the central axis of opening 18 for the valve. The width of the groove is slightly greater than the diameter of opening 18 for the valve.

The groove 19 has the same depth as the recessed segment. On the recessed end surface of the piston, a raised elongated projection 20 with a flat top is formed, extending in the transverse direction and on both sides of the opening in the groove 19. A blind channel 21 is formed in the projection, located approximately in the middle between the walls of the groove 19 and in the middle in the transverse direction of the projection 20. The height of the projection 20 is about one tenth of the depth of the recess. A second projection 22 is formed near the end wall of the groove 19. The second projection 22 has a curved edge, and its maximum height above the recessed end wall is approximately three times greater than the height of the first projection 20.

A combined element consisting of a valve element and an elastic element, molded in one piece from an elastic flexible plastic material, such as polymethyl methacrylate, is installed in a groove 19 on the end surface of the piston 12 and closes the opening 18 for the valve. The said combined element contains a substantially cuboid rod part 23 with a valve element 24, consisting of a plug in the form of a truncated cone, formed in the direction of the end of one surface of the rod part 23. The plug 24 has a free end, the diameter of which is smaller than the diameter of the opening 18 for the valve. The diameter of the plug increases from its free end to a diameter exceeding the diameter of the opening 18 for the valve. The rod part 23 is inserted into the groove 19 with a tight sliding fit in such a way that the plug 24 is received in the opening 18, and the opposite end of the rod part 23 rests on the curved projection 22 at the end of the groove 19. The screw 25 passes through the channel in the rod part 23 in the channel 21 in the projection 20, which passes through the opening in the groove 19. The screw 25 presses the lower part of the rod part 23, bringing it into contact with the projection 20. As a result, the rod part 23 bends between the two projections 20, 22 and the rod part 23 is elastically displaced in such a way as to push the plug 24 into the opening 18, closing the opening 18 to provide an airtight seal.

Due to the elasticity of the rod member 23, if the air pressure outside the end of the piston 12 is higher than the pressure inside the piston 12 by a certain threshold value, the pressure difference will cause the plug 24 to be pushed out of the opening 18, which will cause the rod member 23 to bend and gas to flow through the opening 18, as shown in an enlarged view in Fig. 7. If the pressure difference becomes less than the threshold value, due to the elasticity of the rod member 23, the plug 24 will be pushed back into the opening 18, closing the self-resetting pressure relief valve. Thus, the combined elastic and valve elements 23, 24 together with the opening 18 form a self-resetting pressure relief valve.

The dimensions and shape of the various components of the self-resetting pressure relief valve and the projections formed on the piston end face, as well as the material of the combined damping/resilient element, are selected such that the self-resetting pressure relief valve opens at a specified threshold pressure. The threshold pressure represents the maximum safe pressure the device can withstand.

When in use, when the device is in the position shown in Fig. 1 and 2, i.e. With the levers 10 in their closed position and the piston 12 in the fully retracted position, the user places a boot (not shown) to be put on the drive shaft around the levers 10. The compressed air supply hose is connected to the fitting 4. The user-controlled valve 5 is opened so that compressed air flows through the pipeline in the handle 3 into the space in the main body behind the piston 12. As a result of the action of increased pressure behind the piston 12, the piston 12 moves in a direction away from the domed end of the main body 2. When this happens, the contact surface in the form of a truncated cone of the piston 12 comes into contact with the ends of the levers 10 and moves them radially inward in such a way that the opposite ends of the levers 10, located outside the main body 2, move radially outward, stretching the boot. When the piston 12 comes into contact with the ends of the levers 10, this leads to a maximization of the lever force and, thus, to a minimization, for a given set of levers, of the amount of force that must be applied by the piston 12 to separate the opposite ends of the levers 10. This continues until the levers 10 are fully separated into the deployed position shown in Figs. 3 and 9, and the ends of the levers 10 inside the main body 2 come into contact with the annular section of the piston 12, preventing further movement of the piston 12. The boot can then be placed over the connection 26 on the shaft 27, on which it is to be installed. During this process, the free end of the shaft 27 is received into the main body 2 of the device and into the piston 12, which allows the boot to be positioned at a sufficient distance from the free end of the shaft 27.

Once the boot is properly positioned over connection 26, the user activates user-controlled valve 5 to release air from piston 12. The boot and spring 11 will press levers 10 toward their closed position, with spring 11 continuing to exert force when the boot is no longer extended, pushing piston 12 back to its fully retracted position, with the boot partially positioned over connection 26. Device 1 is then retracted, causing the boot to compress around connection 26 to its original shape. The process is complete and can be repeated in the same manner.

If the air pressure behind piston 12 exceeds a predetermined safety threshold, for example, due to the user continuing to inhale air when the cover is fully extended, the self-resetting pressure relief valve opens, allowing air to pass through opening 18 in piston 12 to limit the pressure behind piston 12 to or near the threshold. If no more air enters the space behind piston 12 and the pressure drops below the threshold, the self-resetting pressure relief valve automatically closes, allowing continued use of the device.

The self-resetting pressure relief valve is designed in such a way that it can be opened sufficiently without the need to move the rod part 23 from the recessed segment 17 or the groove 19 in the piston 12. This prevents or significantly reduces the risk of accidental or intentional retention of the self-resetting pressure relief valve by means of the shaft 27, which is received in the piston 12 during use.

One or more embodiments are described above by way of example only. Many modifications are possible without departing from the scope of legal protection provided by the appended claims. For example, any suitable self-resetting pressure relief valve capable of automatically opening to relieve pressure in a pneumatic actuator when said pressure reaches a predetermined threshold may be used.

Claims (16)

1. A pneumatically controlled device for installing a boot on joints, comprising a pneumatic actuator configured to control, when in use, the stretching of the boot, wherein the pneumatic actuator comprises a piston, wherein the piston is hollow and has an open end to allow the insertion of a shaft into it, over which a cover should be installed when using the device, and contains a supporting surface, a plurality of pivotally mounted levers for receiving and stretching the cover, wherein one end of each lever extends from the device to the free end, and the opposite end of each lever, beyond the point around which the lever can be rotated, is configured to contact the supporting surface, self-resetting pressure relief valve, user-controlled valve, wherein the self-resetting pressure relief valve is located in the piston and is configured to provide for the supply or restriction of the flow of fluid through the piston from one side of the piston to the other. 2. The device according to claim 1, in which the self-resetting pressure relief valve is located in a recess in the piston. 3. The device according to item 1 or 2, in which the self-returning pressure relief valve is located on the end surface of the piston. 4. A device according to any one of the preceding claims, wherein the self-resetting pressure relief valve comprises an opening and a valve element configured to close said opening. 5. The device according to claim 4, containing an elastic element arranged to displace the valve element in the direction of said opening. 6. The device according to claim 5, wherein the elastic element is an elastic flexible rod part or a leaf spring. 7. The device of claim 6, wherein the elastic element is connected to the piston by means of a fastening element that presses it against two contact points on the piston to bias said element so that it presses the valve element in the direction of said opening. 8. A device according to any one of paragraphs 5-7, in which the elastic element and the valve element are made from one piece of material. 9. A device according to any one of paragraphs 5-7, in which the elastic element and/or valve element are made of a plastic material. 10. The device according to any one of paragraphs 4-8, in which the opening includes a passage in the piston. 11. A device according to any of the preceding claims, wherein the piston has a supporting surface in the form of a truncated cone.