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Title:
HUB AND SHAFT CONNECTION WITH RELEASE MECHANISM
Document Type and Number:
WIPO Patent Application WO/2009/071089
Kind Code:
A1
Abstract:
A hub and shaft connection (1) wherein a key (6) mounted in a shaft (2) and a groove (5) formed in the hub (4) transmit a torque, where a release means (7) is mounted in a boring (12) in the hub, the boring extending from the outer side of the hub to the groove (5) at which the release means (7) has a gripper part (13) provided outside the hub (4) and an engagement member (14) having a first extreme position at a position within the groove (5), and which may be displaced to a second extreme position outside the groove (5), the release means being designed with means for retaining the engagement member (14) in the first extreme position, where the key (6) is provided a recess (8), and where the engagement member (14) may engage when the release means (7) is in its first extreme position, wherein the release means (7) is selected among positioning bolts and screw threaded units together with a hub (4) which is provided with a screw thread.

Inventors:
JESPERSEN POUL ERIK (DK)
Application Number:
PCT/DK2008/050287
Publication Date:
June 11, 2009
Filing Date:
December 04, 2008
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
FLEX TRIM AS (DK)
JESPERSEN POUL ERIK (DK)
International Classes:
F16D1/108; B24B45/00
Foreign References:
EP0427090A21991-05-15
EP0916854A11999-05-19
DE3120871A11982-12-23
Attorney, Agent or Firm:
PATRADE A/S (Aarhus C, DK)
Download PDF:
Claims:

CLAIMS

1. A hub and shaft connection (1) wherein a key (6) mounted in a shaft (2) and a groove (5) formed in the hub (4) transmit a torque, where a release means (7) is mounted in a boring (12) in the hub, the boring extending from the outer side of the hub to the groove (5) at which the release means (7) has a gripper part (13) provided outside the hub (4) and an engagement member (14) having a first extreme position at a position within the groove (5), and which may be displaced to a second extreme position outside the groove (5), the release means being designed with means for retaining the engagement member (14) in the first extreme position, where the key (6) is provided a recess (8), and where the engagement member (14) may engage when the release means (7) is in its first extreme position, characterised in that the release means (7) is selected among positioning bolts and screw threaded units together with a hub (4) which is provided with a screw thread.

2. Hub and shaft connection according to claim 1, characterised in that the release means (7) is provided with a spring (11) pressing the engagement member (14) against its first extreme position in the groove (5).

3. Hub and shaft connection according to claim 1-2, characterised in that an axis (9) through the boring of the release means in the hub (12) and through the cutout (8) in the key intersects the rotary axis (10) of the shaft.

4. Hub and shaft connection according to claim 1-2, characterised in that an axis (9) through the boring of the release means in the hub (12) and through the cutout (8) in the key does not intersect the rotary axis (10) of the shaft.

5. Hub and shaft connection according to any preceding claim, characterised in that the key (6) is selected among the following key types: parallel key, slide key, Woodruff key.

6. Use of a hub and shaft connection according to any preceding claim in a grinding/sanding/trimming/polishing machine (16).

7. Use of a hub and shaft connection according to claim 6, where the hub (4) is provided in a grinding/sanding/trimming/polishing tool (15) and where the shaft (2) is mounted in a drive unit (18) for driving the grinding/sanding /trimming/polishing tool (15).

8. Use of a hub and shaft connection according to claim 6 or 7, where the grinding/sandmg/trimming/polishing tool (15) is placed in a roundabout (19) as part of a grinding/sanding/trimming/polishing machine (16).

Description:

HUB AND SHAFT CONNECTION WITH RELEASE MECHANISM

Field of the Invention

The present invention concerns a hub and shaft connection wherein a key mounted in a shaft and a groove formed in the hub transmit a torque, where a release means is mounted in a boring in the hub, the boring extending from the outer side of the hub to the groove at which the release means has a gripper part provided outside the hub and an engagement member having a first extreme position at a position within the groove, and which may be displaced to a second extreme position outside the groove , the release means being designed with means for retaining the engagement member in the first extreme position, where the key is provided a recess , and where the engagement member may engage when the release means is in its first extreme position.

The invention also concerns use of such a hub and shaft connection in a grinding/sanding/trimming/polishing machine.

Background of the Invention

When using hub and shaft connections where power transmission is effected through a key and groove connection, it is often necessary to secure the hub against displacement in axial direction. Until now, this has been provided by means of e.g. a combination of the shaft design and lock rings or clamps. Frequently, this requires that the shaft, which is standard equipment, has to be modified.

The drawback of this is that it prevents rapid dismounting and mounting of the hub for equipment where such operations are often to be performed, and that standard equipments has to be modified, entailing additional costs.

This is e.g. the case with grinding/sanding/trimming/polishing machines where the machines that may include a large number of grinding heads are rapidly to be reconfigured with other grinding heads, depending on whether rough grinding, fine trimming or e.g. polishing is to be performed.

From EP 0 427 090 is known a hub and shaft connection with a release means which is mounted in a boring in the hub and which engages a key in the shaft. However, this publication does not provide for replacement of the release means in case of failure.

Object of the Invention It is the purpose of the invention to provide a hub and shaft connection that enables secure retention of the hub on the shaft during use and which simultaneously provides the option of quickly releasing the hub from the shaft and mounting it on another hub. Besides, modifications of the shaft is to be avoided and the solution is to provide for replacement of the release means in case of failure.

Description of the Invention

According to the present invention, this is achieved by a hub and shaft connection of the kind specified in the introduction which is peculiar in that the release means is selected among positioning bolts and screw threaded units together with a hub which is provided with a screw thread.

Hereby it becomes possible to retain the release means in the hub while at the same time it enables replacing the release means if it becomes defective. Besides, the release means is provided in a threaded unit as a standard component, thereby reducing the cost of the invention.

Alternatively, there is selected a positioning bolt of the type where a number of balls are actuated by a spring-biased locking mechanism. The balls are displaced radially in relation to the positioning bolt. In the rest position of the positioning bolt, the balls are displaced to their extreme position outside the bolt, whereby they enable engagement with the hub or the key, thereby retaining it relative to the shaft. When the positioning bolt is actuated, the balls are displaced inwards such that they do not overrun the outer surface of the positioning bolt, whereby it becomes possible to remove the positioning bolt and thereby release the hub. The advantage of using a positioning bolt is that there are a wide range of cheap standard components. The positioning bolt may be of a type as described in e.g. US patent no. 6,386,789. Unlike a screw threaded unit, the positioning bolt has a smooth cylindric surface.

The release means is mounted in a boring from the outer side of the hub to the groove such that the release means is provided access to engage a cutout in the key when the latter is disposed in the groove and at an axial position opposite the boring in the hub. When the release means engages the key in its first extreme position, the hub is thereby retained at the desired axial position on the shaft. The release means is designed such that it has a gripper part. The gripper part is disposed outside the hub and enables an operator to move the release means easily and without use of tools from its first extreme position to its second extreme position, which is a position of the engagement member of the release means outside the groove, whereby the release means is no longer in engagement with the key. When the release means is no longer engaging the key, it is possible to displace the hub axially in relation to the shaft. The hub may hereby be released from the shaft for possibly mounting another hub. The release means is provided with means that ensure retention of the engagement member in the first extreme position such that the hub does not come loose during use. This enables rapid replacement of the hub besides that the invention is provided without modification of the shaft as modification is limited to the key.

The invention can be applied in a grinding/sanding/trimming/polishing machine where the hub is provided in a grinding/sanding/trimming/polishing tool, and where the shaft is mounted in a motor for driving the grinding/sanding/trimming/polishing tool. The grinding/sanding/trimming tool may be placed in a grinding/sanding/trimming/polishing machine. Typically, such a machine will contain 12 - 24 grinding/sanding/trimming/polishing tools. The present invention enables a substantial reduction of the changeover time for the grinding/sanding/trimming/polishing machine.

The release means according to the invention may be designed in other embodiments than those described above, such as with bayonet socket, instead of e.g. spring action. The essential feature is that the release means has two extreme positions, inside and outside the groove, respectively, and that by the release means, means are provided for retaining the release means in the extreme position within the groove, and that the release means is provided with a grip outside the hub.

According to a further embodiment, the hub and shaft connection according to the invention is peculiar in that the release means is provided with a spring pressing the engagement member against its first extreme position in the groove. The spring is to be of such hardness that the release means is engaged even under the action of the centrifugal force from possible rotation of hub and shaft. This embodiment is particularly advantageous since the engagement member of the locking means is retained in the hub, and the risk that the release means is lost during use is minimised.

According to a further embodiment, the hub and shaft connection according to the invention is peculiar in that an axis through the boring of the release means in the hub and through the cutout in the key intersects the rotary axis of the shaft. A particularly advantageous embodiment is here that the engagement member of the release means moreover goes through a plane perpendicular to the rotary axis of the shaft. The advantage of this is that the boring in the hub and the cutout in the key are simple to make as well as a possible screw thread in the hub.

According to a further embodiment, the hub and shaft connection according to the invention is peculiar in that an axis through the boring of the release means in the hub and through the cutout in the key does not intersect the rotary axis of the shaft. A particularly advantageous embodiment is here that the engagement member of the release means goes through an axis perpendicular to the side face of the key in a plane perpendicular to the rotary axis of the shaft. The advantage thereof is that the torque transmission from the shaft to the release means becomes minimal whereby the durability of the release means is increased.

According to a further embodiment, the hub and shaft connection according to the invention is peculiar in that the key is selected among the following key types: parallel key, slide key, Woodruff key. The important feature with regard to the choice of key type is that the key has a size that enables designing a cutout which corresponds to the size of the engagement member of the release means, and that the key is selected under consideration of the tolerance requirements for fitting into the groove.

Description of the Drawing

The invention is explained more closely in the following with reference to the drawings, where:

Fig. 1 shows a side view of a hub and shaft connection; Fig. 2 shows a sectional view of a hub and shaft connection with a release means at its first extreme position; Fig. 3 shows a sectional view of a hub and shaft connection with a release means at its second extreme position;

Fig. 4 shows a sectional view of a hub and shaft connection in an embodiment where the release means is engaging through the side face of the key;

Fig. 5 shows an elementary sketch of a grinding/sanding/trimming/polishing tool and a grinding/sanding/trimming/polishing machine; and Fig. 6 shows a schematic drawing of a positioning bolt.

Detailed Description of the Invention The hub and shaft connection 1 shown in Fig. 1 shows a hub 4, a shaft 2 and a key 6. The boring 12 for the release means (not shown) is shown from two different directions. I-I defines the section of Fig. 2 and Fig. 3. H-II defines the section of Fig. 4.

The sectional view of a hub and shaft connection 1 shown in Fig. 2 shows a shaft 2 with a groove 3 and a detail of a hub 4 with a groove 5. In the groove 3 of the shaft is mounted a key 6 which is also situated within the groove 5 of the hub. A torque may thereby be transmitted through the sides of the key and groove connection.

The axis 9 of the boring 12 of the release means in the hub 4 intersects the rotary axis 10 of the shaft 2 in the embodiment of the hub and shaft connection 1 shown in Fig. 2.

A release means 7 is fitted in a boring 12 in the hub 4. The shown release means 7 is provided with an inner spring 11 urging the release means 7 against its first extreme position. The release means 7 is additionally provided with an external screw thread that corresponds to a corresponding inner screw thread in the hub 4. The release means 7 has a gripper part 13 outside the hub 4 and an engagement member 14 for engaging the key 6. By operating the gripper part 13, the engagement member 14 may be

displaced from a position in full engagement with the key 6 to a position outside the key 6. On Fig. 2, the release means is shown in its first extreme position. The release means is engaging a cutout 8 in the key. The hub 4 is thereby secured against axial displacement. The sectional view shown in Fig. 3 of a hub and shaft connection differs from Fig. 2 in that the release means 7 is shown in its second extreme position. The release means 7 is not engaging the cutout 8 in the key 6. The hub 4 is thereby released, and axial displacement of the hub 4 is possible.

The sectional view of a hub and shaft connection 1 shown in Fig. 1 shows a shaft 2 with a groove 3 and a detail of a hub 4 with a groove 5. In the groove 3 of the shaft is mounted a key 6 which is also located within the groove 5 of the hub. Thereby a torque can be transmitted through the sides of the key and groove connection.

The axis 9 of the boring 12 of the release means in the hub 4 does not intersect the rotary axis 10 of the shaft 2 in the embodiment of the hub and shaft connection 1 shown in Fig. 4.

A release means 7 is fitted in a boring 12 in the hub 4. The shown release means 7 is provided with an inner spring 11 urging the release means 7 against its first extreme position. The release means 7 is additionally provided with an external screw thread that corresponds to a corresponding inner screw thread in the hub 4. The release means 7 has a gripper part 13 outside the hub 4 and an engagement member 14 for engaging the key 6. By operating the gripper part 13, the engagement member 14 may be displaced from a position in full engagement with the key 6 to a position outside the key 6. On Fig. 2, the release means is shown in its first extreme position. The release means 7 is not engaging a cutout 8 in the key 6. The hub 4 is thereby released, and axial displacement of the hub 4 is enabled.

Fig. 5 shows a grinding/sanding/trimming/polishing tool 15 of which the hub and shaft connection forms a part. The hub 4 with release means 7 is provided on a grinding/sanding/trimming/polishing wheel 17. The shaft 2 with key 6 is shown before mounting the grinding/sanding/trimming/polishing tool. The

grinding/sanding/trimming/polishing tool forms part of the larger grinding machine where the grinding/sanding/trimming/polishing tools may be provided in a roundabout 19 that typically consists of 12-24 grinding/sanding/trimming/polishing tools which are connected to each their, or to one common, drive unit 18.

Fig. 6 shows a schematic drawing from US patent 6,386,789 of a positioning bolt which can be used as release means. The positioning bolt has a smooth cylindric surface. It is provided with balls engaging grooves in the boring in the hub, or engagement outside the hub in case that the positioning bolt extends completely through the hub and the key, or engages grooves in the key.

The invention is not limited to the embodiments shown and described above in the Figures. Other embodiments, including other embodiments of e.g. hub, key or release means, are possible within the scope of this invention and the matter specified in the claims.