Tool free bolt system for a saw blade

Patent metadata

Field	Value
Publication number	US-2016288359-A1
Application number	US-201415037865-A
Country	US
Kind code	A1
Filing date	Nov 17, 2014
Priority date	Nov 25, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

A bolt assembly ( 100 ) enables a user to change a circular blade ( 160 ) on a power tool ( 200 ) without the use of tools. The bolt assembly includes a bolt body ( 110 ) that has a bolt head ( 132 ) and a shank ( 136 ) that extends axially from the bolt head. The bolt head has a shoulder and the shank has external threads that mate with a threaded bore ( 220 ) of a drive shaft ( 212 ) of the power tool. A grip body ( 130 ) is formed circumferentially around the bolt head to facilitate rotation of the bolt body by the user's hand. An upper washer ( 114 ), a needle roller thrust bearing ( 116 ), and a lower washer ( 118 ) are positioned on the bolt head and retained with a retaining clip ( 120 ). The bolt body is rotated to press the lower washer against a clamping surface of the circular blade. The bolt assembly permits rotation of the lower washer relative to the bolt body without rotating the bold body.

First claim

What is claimed is:

1 . A bolt assembly for securing a tool disc to a power tool, comprising:
a bolt body having a bolt head and a shank extending axially from the bolt head, the bolt head having a bearing surface that faces the shank and the shank having external threads that are matably receivable in a threaded bore of a shaft of the power tool; a grip body extending radially from and circumferentially about the bolt head, the grip body being configured to rotate the bolt body; a lower washer positioned between the bearing surface and the shank, the lower washer being rotatable about the bolt head and having a contact surface configured to be pressed against a clamping surface of the tool disc; and a bearing positioned between the bearing surface and the lower washer, the bearing being configured to allow the lower washer to rotate relative to the bolt body without rotation of the bolt body.

2 . The bolt assembly of claim 1 , wherein the bolt head has a first shoulder protruding radially from the bolt head, the first shoulder defining the bearing surface.

3 . The bolt assembly of claim 1 , wherein the bolt head has a first shoulder protruding radially from the bolt head, the bolt assembly further comprising an upper washer positioned between the first shoulder and the bearing, the upper washer defining the bearing surface.

4 . The bolt assembly of claim 1 , wherein the bearing is configured as a needle roller thrust bearing having a plurality of radially extending rollers.

5 . The bolt assembly of claim 2 , wherein the grip body has an inner web portion attached to the bolt head and an outer cylindrical portion disposed radially outward from the inner web portion, the outer cylindrical portion having a lower surface that is set back from the contact surface of the lower washer.

6 . The bolt assembly of claim 1 , wherein the lower washer defines an upper cavity opening towards the bearing surface and a lower cavity opening towards the shank, the bearing being at least partially slidably nested within the upper cavity of the lower washer.

7 . The bolt assembly of claim 5 , wherein the outer cylindrical portion of the grip body defines a grip cavity opening towards the shank, the lower washer being at least partially slidably nested within the grip cavity.

8 . The bolt assembly of claim 6 , wherein the bolt head defines an annular groove positioned proximate to the shank, the bolt assembly further comprising a retaining clip inserted into the annular groove and configured to retain the bearing and the lower washer on the bolt head.

9 . The bolt assembly of claim 8 , wherein the bolt head has a lower surface facing the shank, and wherein the retaining clip and the lower surface are nested within the lower cavity of the lower washer.

10 . The bolt assembly of claim 5 , wherein bolt head has a second shoulder spaced from the first shoulder in a direction axially away from the shank, the inner web portion of the grip body being configured to fill the space between the first shoulder and the second shoulder so as to axially secure the grip body to the bolt body.

11 . The bolt assembly of claim 10 , wherein the bolt head has at least one flat surface extending parallel to shank, the inner web portion of the grip body being configured to surround the flat surface so as to rotationally secure the grip body to the bolt body.

12 . The bolt assembly of claim 1 , wherein the bolt head defines an internal cavity opening away from the shank, the internal cavity having a circumferential profile corresponding to a tool configured to rotate the bolt body.

13 . The bolt assembly of claim 1 , wherein the bearing is formed from one or more of a low friction plastic, a low friction metal, or an oil impregnated sintered metal.

14 . The bolt assembly of claim 1 , wherein the grip body includes a grip surface disposed about a circumferential periphery of the grip body and configured to facilitate rotation of the grip body by a hand of a user, the grip surface including one or more of an elastomeric material having high surface friction, a plurality of grip features adhered to the grip body, and a plurality of undulations formed or cut into the grip body.

15 . A power tool, comprising:
a rotatable drive shaft having a threaded bore; a circular blade mounted to the end of the drive shaft; an inner blade washer and an outer blade washer mounted on the drive shaft, the inner blade washer positioned on an inner side of the circular blade and the outer blade washer positioned on an outer side of the circular blade; and a bolt assembly configured to press the outer blade washer against the circular blade and the inner blade washer so as to secure the circular blade to the drive shaft, the bolt assembly including:
a bolt body having a bolt head and a shank extending axially from the bolt head, the bolt head having a bearing surface and the shank having external threads that are matably receivable in the threaded bore of the drive shaft;
a grip body extending radially from and circumferentially about the bolt head, the grip body being configured to rotate the bolt body;
a lower washer positioned between the bearing surface and the shank, the lower washer being rotatable about the bolt head and having a contact surface configured to be pressed against the outer blade washer; and
a bearing positioned between the bearing surface and the lower washer, the bearing being configured to allow the lower washer to rotate relative to the bolt body without rotation of the bolt body.

16 . The power tool as claimed in claim 15 , wherein the grip body of the bolt assembly has an inner web portion attached to the bolt head and an outer cylindrical portion disposed radially outward from the inner web portion, the outer cylindrical portion having a lower surface that is set back from the contact surface of the lower washer so as to provide clearance from the outer blade washer.

17 . The power tool as claimed in claim 15 , wherein the lower washer of the bolt assembly defines an upper cavity opening towards the bearing surface of the bolt body and a lower cavity opening towards the shank of the bolt body, the bearing being at least partially slidably nested within the upper cavity of the lower washer.

18 . The power tool as claimed in claim 15 , wherein the outer cylindrical portion of the grip body defines a grip cavity opening towards the shank of the bolt body, the lower washer being at least partially slidably nested within the grip cavity.

19 . The power tool as claimed in claim 17 , wherein the bolt head of the bolt assembly defines an annular groove positioned proximate to the shank, the bolt assembly further comprising a retaining clip inserted into the annular groove and configured to retain the bearing and the lower washer on the bolt head.

20 . The power tool as claimed in claim 19 , wherein the bolt head of the bolt assembly has a lower surface facing the shank, and wherein the retaining clip and the lower surface are nested within the lower cavity of the lower washer.

Assignees

• Bosch Gmbh Robert

Inventors

• Patrick Eiswerth

Classifications

• B27B5/32 Primary

  Devices for securing circular saw blades to the saw spindle · CPC title

• B27B5/30

  for mounting or securing saw blades or saw spindles · CPC title

• B27B5/29

  Details; Component parts; Accessories · CPC title